With the recent announcement that the entirety of The CW's Arrowverse has been renewed going into 2019, it seems an apt time to look forward at what is coming next for DC's television universe. Last year's crossover event, "Elseworlds," revealed that a greater threat than The Monitor was coming to the multiverse. With 2019's crossover officially announced, fans can expect to see quite a few familiar faces. Fans of the DC Comics' event, "Crisis on Infinite Earths" will likely be aware that the "greater threat" being referenced in "Elseworlds" is almost certainly the Anti-Monitor, and with him comes the greatest threat that any of the heroes of the multiverse have ever faced.

Luckily, over the course of their careers, Oliver Queen, Barry Allen, and Kara Danvers have met quite a few friends and allies who could stand with them against the Anti-Monitor. Here's our list for the 10 characters we'd like to see return for "Crisis on Infinite Earths"

10 10. Superman

Tyler Hoechlin as Superman on Supergirl

He may seem like an obvious inclusion given his substantial role in last year's crossover event, but anything could happen. As it stands, it's hard to imagine such a huge, potentially world-changing event without the Man of Steel after his pivotal role in "Elseworlds." Besides the raw power that Superman brings to the table, Tyler Hoechlin is adorably charismatic as Clark Kent and its a joy seeing a hopeful, lighthearted Superman so brilliantly brought to life by his performance. Though Clark Kent is currently anticipating the arrival of his first child with Lois Lane, "Crisis on Infinite Earths" promises to be the kind of multiverse shattering event that he can't afford to miss.

9 9. Kid Flash

Keiynan Lonsdale's Kid Flash

Keiynan Lonsdale's Wally West has had a bit of a rough ride on The CW. While Lonsdale does a wonderful job bringing the youthful and enthusiastic speedster to life, Wally has been plagued with limited screen time and poor development. While fans were enthused to see Wally finally gain his powers, he never stepped out of Barry Allen's shadow.

After a brief stint on Legends of Tomorrow, Wally West disappeared from the Arrowverse entirely earlier this season. With the arrival of the Anti-Monitor and a multiverse-wide crisis, it may be the perfect time for Kid Flash to return and hopefully carve out his own identity as a hero.

8 8. Citizen Cold

One thing we learned from The Monitor in last year's crossover was that he had only been testing each of the Earth's individually. Earth-1's success came thanks to help from Earth-38 in the form of Superman and Supergirl. It makes sense for the heroes of Earth-1 to recruit more allies from across the multiverse to face the Anti-Monitor. One of these heroes could (and should) be fan favorite Leonard Snart of Earth-X. While Wentworth Miller is no longer contractually tied to the Arrowverse, he has left the door open for his return. What better time to come back than to save the entirety of the multiverse? Though Leonard Snart lacks any sort of super-powered abilities (besides dry humor and cold puns,) he does possess the kind of upbeat and optimistic attitude that inspires those around him to keep fighting even when hope seems lost, an important quality if the threat is as great as The Monitor claims.

7 7. The Ray

If Leonard Snart is coming back to help protect the multiverse, then why not The Ray? Ray Terrill hasn't been on any of the live-action Arrowverse shows since his role in the 2017 crossover event, "Crisis on Earth-X." Since then, his lover and ally, Earth-X's Leonard Snart, has made a handful of appearances on The Flash and Legends of Tomorrow. In his last appearance, Snart revealed that the pair were finally getting married. Bringing Ray along with Snart would keep the stakes personal as they fight to protect each other and the multiverse. Ray is also one of the most powerful heroes in the known multiverse, so it makes sense for the heroes to reach out in their time of need.

6 6. Vixen (Amaya Jiwe)

Amaya's Vixen on Legends of Tomorrow

Legends of Tomorrow actress Maisie Richardson-Sellers quickly became a fan favorite after her introduction in season 2. This led her to be brought back in a new role after her Amaya's arc had concluded. While her new role is a whole lot of fun, it makes sense for the heroes of Earth-1 to recruit their best. Frankly, Amaya fits that bill better than Richardson-Sellers' other character, Charlie. Amaya consistently proved to be one of the most competent members of the crew during her time on the Waverider. She's also one of the only members of the Legends with formal training. Though she retired to accept her destiny and live out a peaceful life in Zambezi, it wouldn't be too much of a stretch for the Legends, or even Barry Allen, to pluck her out of the timeline to face one last powerful enemy and save the multiverse. Speaking of the Legends...

5 5. The Legends of Tomorrow

Legends of Tomorrow Episodes

Yes, yes. Technically, the Legends are more than one character. And technically they are still going strong as the much weirder cousin to the other shows in The CW's Arrowverse. But the Legends were very noticeably absent from last year's crossover. Sure like with most of the crossovers "Elseworlds" was very much centered on Barry Allen and Oliver Queen.

And yes it is difficult enough to juggle the expansive cast of Legends of Tomorrow on its own. However, with the greatest crisis the multiverse has ever seen, it makes sense to bring in the Legends.

4 4. Arsenal

Arrow's Roy Harper/Arsenal

Again, technically Colton Haynes' Roy Harper has returned as a series regular on Arrow. Despite that, he has been largely absent from the season thus far. Besides a few brief appearances in season 7's "flash-forward" story-line, Roy Harper has been totally missing from the series he is supposedly a regular on. Thanks to a mention from future Dinah Drake, we know that the pair met at some point in the past. Whether that means Roy will appear in the modern day timeline of season 7 is still unknown. Though Roy doesn't have any superpowers, he was trained by Oliver to be as efficient and deadly as him. Considering that so much depends on Oliver Queen, it makes sense for Roy to have his back.

3 3. Deathstroke

Slade Wilson aka Deathstroke in Arrow Season 6

As always, it is uncertain what DC's current policy is on whether or not The CW can use Slade Wilson. If included, Deathstroke would be one of the more surprising characters to appear. Unlike nearly every other entry on this list, Deathstroke has never appeared on an Arrowverse show outside of Arrow.  If he is included, he would be a powerful ally given his near unmatched fighting capabilities and a tactical mind that rivals that of Oliver Queen.

2 2. Gypsy

The Flash Gypsy Jessica Camacho

Since the threat posed by the Anti-Monitor is a danger to all of the multiverse, it makes sense that people who can freely traverse will be a great asset. With the possibility of Cisco giving up his powers, Gypsy may be the Arrowverse's best shot. Whether or not Cisco actually takes that step, it certainly wouldn't hurt to have two breachers. It could also serve as a chance for both Cisco and Cynthia to get some closure. Perhaps they could even rekindle their relationship if something dramatic happens like say, the entirety of the multiverse is rolled into one singular reality?

1 1. Mon-El

Supergirl -- Mon-El

Though he started out a little rough around the edges, Mon-El quickly grew into one of Earth-38's greatest heroes. Currently, he resides in the far future of Earth-38. Despite that, it doesn't seem like too much of a stretch to bring him back. Like Cisco and Gypsy, Mon-El and Kara have a bit of unfinished business. If "Crisis on Infinite Earths" is as world-shattering as we expect it to be, this may be their last chance.

NEXT: Next Arrowverse Crossover Is 'Highly Likely' To Kill a Superhero