It's a copy of X-Men #141's cover from [***Days of Future Past***][1].

[![enter image description here][2]][2]

Characters in *that* poster.

Top Left - Bottom Right

 1. Cyclops
 2. Colossus
 3. Storm
 4. Nightcrawler
 5. Angel
 6. Iceman
 7. Beast
 8. Sprite
 9. Magneto
 10. Quicksilver
 11. Jean Grey
 12. Wolverine
 13. Forge?
 14. Polaris
 15. Havoc
 16. Banshee


  [1]: https://en.wikipedia.org/wiki/Days_of_Future_Past
  [2]: https://i.sstatic.net/mO13C.jpg