Every type in the Pokémon universe has its stronger and weaker species, especially in terms of their appearances in the anime. Rock-types were the first type to be properly showcased as a threat at the very start of Ash's journey, when he was immediately swept aside by Brock with his Geodude and Onix.
Rock-types come in all shapes and sizes, usually incorporating rocks and stones into their general designs and appearances, or utilizing them with their moves. Rock-types do have five weaknesses, which can be increased even further depending on the secondary typing of that specific Pokémon, but they're generally given high defensive stats that reflect their rock-hard skin and mentality.
10 Aggron's Potential Has Never Truly Been Unlocked In The Anime
Aggron is a naturally formidable and intimidating Pokémon, and it's somewhat surprising that it isn't given a particularly strong or dominant showing in the anime. Ash's main Sinnoh rival, Paul, owned one, and it opened up their match at the Lily of the Valley Conference, battling well against Ash's Pikachu before falling to his Infernape.
The fact that the well-respected Steven Stone is seen using an Aggron to easily deal with Team Rocket is a testament to how Aggron is considered to be one of the strongest Steel/Rock dual-types in the entire Pokédex. Given that it can also utilize Mega Evolution, Aggron should certainly be used more by Trainers who strive to be the best.
9 Geodude And Golem Especially Are Often Used By Rock-Loving Trainers
The Geodude evolutionary line was immediately introduced to the franchise under the ownership of Pewter City Gym Leader Brock. It easily defeated Ash's Pidgeotto in the rematch before losing to a supercharged Pikachu. Brock continued to use Geodude as one of his most loyal companions.
The second form of the evolutionary line, Graveler, hasn't been used by enough Trainers to be viewed as anything more than a background Pokémon, but its evolved form, Golem, has been used by the likes of Giovanni and Gary Oak. A Golem belonging to Biker gang member Chopper even defeated Ash's Bulbasaur.
8 Rhyperior Was Too Much For Ash's Grotle To Handle
When Ash faces off against Palmer in Pokémon Diamond & Pearl with his Grotle against Palmer's Rhyperior, the latter is initially unfazed and looks in control. As the battle progresses, Grotle demonstrates new levels of power and drags an intense battle out of Rhyperior.
However, ultimately the evolved form of Rhyhorn and Rhydon is too much for Grotle, and Rhyperior emerges victorious. Rhydon had previously felt like a completed final evolution Pokémon, and the introduction of Rhyperior in Generation IV made it even more formidable. Rhyhorn was never given a particularly strong showing in battle, and Rhydon only ever seemed to appear to show off its Lightning Rod ability when facing Ash's Pikachu. Neither make a lasting impression.
7 Byron's Bastiodon Has Rock-Solid Defense
The only appearance of Rock/Steel dual-type Bastiodon in the anime is under the ownership of Byron, Roark's father and also a Gym Leader. It was first shown battling Roark's Rampardos before the battle was called off due to outside interruptions, and was later used in a Gym Battle against Ash.
Bastiodon was able to negate Chimchar's attacks with its own defensive prowess before easily knocking it out. It went on to lose eventually to Ash's Gliscor, but still drew out an intense and entertaining bout in the process.
6 Roark's Dangerous Cranidos Evolved Into A Rampardos And Caused Even More Problems For Ash
When Ash faced Oreburgh's Rock-type Gym Leader Roark, he lost Aipom to Roark's Cranidos, which also tired out Pikachu and Turtwig — meaning that Roark's Onix could finish the job and clinch the win. Cranidos evolved into the intimidating Rampardos while fending off a a large scale Team Rocket attack.
This made Ash's job even tougher when the rematch came around, and sure enough, Rampardos easily defeated Pikachu and Aipom before falling to Turtwig once again. Its ability to use powerful physical moves, as well as its diverse overall moveset, makes it one of the fiercest and most formidable Rock-type Pokémon.
5 Nihilego Tormented Lillie And Her Family
Nihilego is a Pokémon and an Ultra Beast that showcases its strength and ominous nature through more than just battling. As events in the Sun & Moon anime unfold, it's revealed that Nihilego was the mysterious Pokémon that attacked Lillie when she was younger, scarring her for life and instilling a subconscious fear of Pokémon.
As if that wasn't enough, a Nihilego even proceeds to abduct and possess Lillie's mother, Lusamine, after it puts up an impressive fight against her, Ash, and Gladion. The dual Rock/Poison Parasite Pokémon makes for one of the more sinister encounters in the series, and its power is not to be underestimated.
4 Cilan's Dwebble, And Later Crustle, Was A Loyal Companion
The little Pokémon based on the real life hermit crab, Dwebble joined Cilan's team during their Unova travels and become a valued friend. Small in stature and somewhat unassuming, Dwebble defied expectations and scored some well-earned victories over the likes of Burgundy with her Dewott and Trip with his Gurdurr.
It even evolved when fending off Team Rocket, becoming the much-larger Crustle. Crustle continued to pull off impressive feats, including carrying Ash's Boldore in a tag battle, earning them the win. Dwebble and Crustle are truly among the most underrated Rock-types out there.
3 Nando's Armaldo Almost Won A Match Against Ash By Itself But Came Up Just Short
The dual-type Rock/Bug Plate Pokémon is known as one of the Fossil species in the Generation III games Ruby, Sapphire, and Emerald. In the anime, an Armaldo is used by Nando, who becomes a friendly rival to both Ash and Dawn with battles and contests respectively, when Nando faces off against Ash at the Lily of the Valley Conference.
Armaldo is strong enough to overpower Staraptor and Quilava, even though the latter was the result of a double-knockout. Armaldo was the only one of Nando's Pokémon to defeat any of Ash's, therefore making a mark in the process.
2 Onix Is A Strong And Trusty Friend For Any Rock-Loving Trainer
The image of Brock's Onix suffocating Pikachu and causing Ash to forfeit way back at the beginning of his Pokémon journey is one that fans still remember to this day and will most likely remember for many years to come. While its evolved form, Steelix, has been used by many strong Trainers over the years, so has Onix.
In addition to Brock, the likes of Roark and Grant, other Rock-type Gym Leaders, have also used an Onix in their battles against Ash, with Roark's Onix earning victories over Ash's Turtwig and Pikachu. Even at its weakest, as a first form of the evolutionary line, Onix is still a huge Pokémon and never particularly easy to get past.
1 Lycanroc Has Rock-Hard Power, Drive, And Grit
Introduced to Generation VII with Sun & Moon, Lycanroc is the evolved form of Rockruff, and comes in three unique forms: Midday, Midnight, and Dusk. All three are featured in the anime under the ownership of strong Trainers.
The second Kahuna that Ash challenges in the Alola region, Olivia of Akala Island, specializes in Rock-types and shows off her Midday form Lycanroc. Ash's rival, Gladion, has the Midnight form, while Ash himself has the Dusk form. When Ash and Gladion face off in the final of the Manalo Conference, the 3-on-3 fittingly ends up being Lycanroc versus Lycanroc for the title, which Ash finally wins. Lycanroc's varying forms, its versatility, and its diverse moveset make it the best Rock-type Pokémon.