SPOILERS for The Last Jedi follow.
The Force is one of the most enduring elements of Star Wars, right up there with lightsabers and the Death Star. Central to the Jedi and the Sith's abilities, the Force is created by all living things, surrounding them and binding them together. In the most recent film, The Last Jedi, the Force displays some pretty incredible abilities. Kylo and Rey communicate across light years as if in person. Rain falling on Rey on Ahch-To is transferred to Kylo on the Supremacy. Snoke displays unprecedented control and power. Luke projects his image across the galaxy and temporarily leaves behind physical objects. There is even the possibility that Luke achieves a state of Force nirvana and becomes one with the Force willingly (it's unclear).
This leaves us with one burning question: what else can the Force do? For answers, we turn to the Legends canon, wiped out by Disney pushing the reset button so new creators could tell their own stories. While the feats in The Last Jedi are impressive, they pale in comparison to some of the greatest powers wielded by the Jedi and the Sith. Perhaps, in Episode IX and beyond, we'll see a few of these used by Rey and Kylo Ren.
One of the first things the Legends Expanded Universe did was introduce new traditions of the Force separate from the Jedi and the Sith. Possibly the most mysterious is the order of monks known as the Aing-Tii. Residing far out of reach of the Republic or the Empire, the monks developed their own understanding of the Force. Rather than viewing it as a light corrupted by darkness, or two sides vying for supremacy, they see the Force as a rainbow, neither good nor evil.
This certain point of view allows them to fold space, effectively teleporting objects, themselves, and even spacecraft. On top of that, they can teach this ability to those with seemingly no Force sensitivity. In a "normal's" hands, it is more of a parlor trick than the grand scale the monks are capable of, but still impressive nonetheless.
14 FLOW WALKING
While actual time travel remains out of reach of Force users (thus far), the Aing-Tii are capable of walking through time and viewing events as if they are there themselves. While the Aing-Tii are generally passive in their viewing, they also pass the technique on to others. Its primary wielder is Kylo Ren's Legends counterpart, Jacen Solo. He uses it to view the past and leave impressions for those who come after.
More sinister, he takes others on his journeys, and uses the ability to alter their perception of the past. He first used this ability to turn a Jedi to the dark side, and later attempted to do the same to Luke Skywalker's son. While Luke believes it is possible to walk into the future, the ability is never demonstrated.
A more practical application of the Force, the Shatterpoint ability allows a Force user to see the structural weakness of a solid object, and locate the exact point to strike in order to shatter it to dust. A specialty of Mace Windu, it also allows the user to see shatterpoints in the future, and influence events by "striking" the shatterpoint.
However, the consequences of breaking a shatterpoint could in turn lead to unforeseen consequences, as laid out by Jedi Master/Sith Lord Kreia. Indeed, according to her, even the smallest of actions could be a shatterpoint that leads to further and further ripples in the Force. The concept also shows up in early drafts of A New Hope, allowing the character who would eventually become Luke Skywalker to sense the Death Star's weak point with the Force.
12 FORCE STORMS
Before Snoke showed up to disappoint everyone, Emperor Palpatine was the pre-eminent dark side Force user in the films. Beyond the films, his powers were even greater. After surviving beyond his death on the second Death Star, the Emperor returned to harry the galaxy once again. While achieving immortality through clone bodies was impressive, it was nothing we hadn't seen before from the Jedi.
What truly set Palpatine apart was his ability to create massive wormholes in space with the Force, devastating planets, swallowing ships, and even transporting people across the galaxy. Luke even identified them as planet killers While a massively powerful ability, they were exceedingly difficult to control, and Palpatine's arrogance led to a storm running out of control and consuming him.
11 MALACIA- FORCE NAUSEA
An exceedingly rare Force ability, Malacia uses the Force to tickle a target's inner ear, causing vertigo, nausea, and generally disabling the target. Because it disabled the target without harming them (beyond vomiting), it was generally considered a Jedi technique. Because it was such a delicate technique, though, most Jedi preferred to take a more direct approach.
Malacia was centered around the Jedi philosophy of using the Force to defend, not attack. The greatest master of Malacia was Oppo Rancisis, that big beardy guru Jedi on the Jedi Council in the prequel trilogy. Despite the technique only affecting organics, he used it to great effect during the Clone Wars, combined with his Battle Meditation. Ultimately, though, it did not save him from an untimely demise at the hands of a Dark Jedi.
10 MORICHRO- FORCE PUT-THAT-GUY-IN-A-COMA
Morichro was an exceedingly dangerous Force technique utilized by the Jedi. Based on the theory of the Force trance employed by many Jedi and Sith throughout the galaxy, Morichro allowed a wielder to put others in a Force trance, essentially a coma. While extremely effective at disabling an opponent, it was also a very delicate process, as too much juice could just shut the body down, while not enough and it doesn't work.
One of the only known Morichro users was Jedi Master Yaddle, the second of Yoda's species seen on the Jedi Council in The Phantom Menace. Despite its potential for killing, dark side Force users never utilized the technique, as it required a more delicate and less malicious application of the Force than they usually employed.
9 THOUGHT BOMB
Long before The Phantom Menace, the Sith existed in numbers rivaling that of the Jedi Order. Rather than the Rule of Two Yoda details at Qui-Gon's funeral, the Sith formed an order similar to the Jedi of Lords and apprentices. Because they were so numerous, they frequently came into large-scale conflict with the Jedi and the Republic. Among their number was the Sith Lord Darth Bane, who would enact the Rule of Two that Darth Sidious would eventually fulfill.
In the final conflict between Republic and Sith, Bane tricked his fellow Sith Lords into using a dangerous Force technique called the thought bomb. The Sith Lords poured all their anger and hate into a single point. This point then absorbed the surrounding Force, and detonated, killing thousands of Sith and Jedi and trapping their spirits in unending torment for a thousand years, when they were freed by an enterprising young Jedi.
8 PLAGUEIS AND SIDIOUS' MEGA-RITUAL
Throughout the prequel trilogy, Yoda and other Jedi occasionally make mention of the future being clouded from their sight. A few even mention that the Jedi's overall ability to use the Force is diminished. In actuality, this is the result of a massive ritual carried out by Darth Sidious and his master, Darth Plagueis the Wise.
Borne out of Plagueis's attempts to create life through the Force, it saturated the midi-chlorians of the galaxy with the dark side. It had two unintended side effects: the first, the Jedi were greatly diminished. Second, the Force itself pushed back to right the balance, and created Anakin Skywalker. While Sidious would briefly make use of Anakin, he ultimately brought Plagueis and Sidious's plans crashing down by destroying the Sith and bringing balance to the Force... for a while.
7 SITH ALCHEMY
Emperor Palpatine's evil old space wizard aesthetic remains one of the more iconic elements of the original Star Wars films. The Expanded Universe took that a step further, introducing the concept of Sith alchemy. While the Force is generally accepted as space magic, Sith alchemy really doubles down on it. Primarily used to create monsters like the Leviathans of Corbos, it referred to using the Force to permanently alter an item or living being. It could also reanimate dead bodies as mindless zombies, as well as create incredible deadly poisons and viruses.
While the films don't really depict the use of Sith alchemy, Sidious implies that Darth Vader himself is at least partially an alchemical creation. Sidious himself possibly used Sith alchemy to hide his true wizened face during his days as Senator and Chancellor Palpatine.
Everyone remembers Obi-Wan and Yoda fading into nothing upon their deaths. Moreover, Luke Skywalker's dissipation in The Last Jedi made a whole lot of people pretty mad. Ordinarily, a Jedi can only become one with the Force by dying. In a few instances, however, a Jedi can fully merge with the Force by surrendering completely, and becoming an extension of the Force as a lightsaber is an extension of the Jedi.
Most notably, Anakin Skywalker achieves Oneness not once but twice, making a miraculous short-range hyperspace jump, and saving Ahsoka Tano from the brink of death on the Force nexus world of Mortis. Also notably, Kylo Ren's Legends counterpart Jacen Solo achieves Oneness and becomes a being of glowing light to face down an existential threat to the galaxy. Perhaps Kylo or Rey will follow in Jacen's footsteps in the future.
5 JEDI LIGHTNING
Along with looking like an evil space wizard, Emperor Palpatine cemented the image with his ability to shoot lightning from his hands. An extremely powerful Force technique, it later became the signature of the Sith and other Dark Jedi, including Count Dooku in Attack of the Clones. As an inherently destructive power, it was considered by many to be a power restricted to the dark side.
However, a few Jedi were able to make use of the technique. While mostly an invention of video games, because players really like being able to zap enemies with lightning, Luke Skywalker was able to utilize Force lightning as he grew older and more experienced with the Force. His descendant, Cade, would later use Force lightning to heal, although it brought him dangerously close to the dark side.
4 FORCE PHASE
One of the most overtly magic Force powers, Phase allows a Force user to walk through solid matter, including doors and walls. Demonstrated by only two Jedi across the entire Legends continuity, it was most famously used by the Dark Woman. An Old Republic Jedi, the Dark Woman delivered conehead Jedi Ki-Adi-Mundi to the Order. She also briefly trained assassin Aurra Sing, briefly seen in The Phantom Menace during the podrace.
The technique was never demonstrated again until a young Jedi of Luke's new Order in the New Republic used it to escape an attack by Mandalorians. Not even Luke or his nephew Jacen were able to use it, but perhaps a Force user in future Disney movies will pull it out of the Legends universe.
3 FORCE SIGHT
While Obi-Wan teaches Luke to extend and empower his senses through the Force, there are techniques he never shares. Among them is the ability to literally see through the Force. An innate ability of the blind Miraluka species, it involves using the Force to detect the life energy of those around them. Blind Jedi, such as Kreia, would also use the technique to overcome their deficiency. Many Jedi able to use Force sight claim that is superior to regular sight.
It even (maybe) shows up in the Disney canon, not just with Kanan Jarrus in Star Wars: REBELS, but also Blind Totally-Not-A-Jedi Guy Chirrut, who operated pretty effectively without sight in Rogue One. Kreia also reveals that overuse of the ability can lead to one's eyes atrophying and becoming useless, similar to a Miraluka's. The ability could also be used to overcome temporary blindness caused by flash grenades, as both Obi-Wan Kenobi and Darth Bane demonstrate.
2 FORCE DRAIN
One of the most powerful and chilling Force abilities, Force Drain was exclusively employed by the Sith. While on a low level, it would drain a small amount of life force from a single human, it could be scaled up massively to drain all life from an entire planet. Most famously employed by Darth Nihilus in Knights of the Old Republic 2, Force Drain involved literally devouring the Force from a living being.
The ability is brought to its full potential by the Sith Emperor Vitiate, who drains multiple planets in order to grow more powerful. While Nihilus devoured the Force to attempt to fill the void within himself, Vitiate was able to augment his own strength with it. Using this ability, he grew to be one of the most powerful Force users in the Legends canon.
1 SEVER FORCE
This is the Jedi's ultimate technique, and their final resort. Using the Force, they block off a Force user's ability to feel the Force, severing the connection irreversibly. First used by ancient Jedi Nomi Sunrider to stop the Sith Lord Ulic Qel-Droma, the technique would later be used on several Sith and Jedi. Most notable was the Jedi Exile of Knights of the Old Republic 2, who blocked herself off from the Force in order to shield herself from the outcry caused by the death of Malachor V.
Unfortunately for her, she did such a good job of it that a wound in the Force was created. Others sought to exploit this wound, and a council of Jedi Masters attempted to sever her connection again. While the technique would be lost for thousands of years, it would later resurface with Jacen Solo, who used it to sever Luke Skywalker's son's connection while torturing him in an attempt to turn him to the dark side.