The X-Men's enemies stand among the greatest group of villains in comics. In fact, an argument can be made that the X-Men's villains are the greatest in comics, eclipsing both teams and solo heroes. The proof is in the pudding. X-Men villains like Sabretooth and Magneto were so popular that they got spots on the X-Men. Deadpool went from a second-rate X-Force villain to the most popular character in the world. Apocalypse, Mister Sinister, Mojo, and so many more have become legends in their villainous fields. The Krakoa Era has been very interesting for the X-Men. When the mutant country was established, all mutants who joined the nation received clemency from Krakoa.
Source:https://www.cbr.com/xmen-comics-orchis-founders-history/