2 player variants "Horde" and "AntiChess" will be added soon. We have both AntiChess and Horde in 4 Player Chess already, by the way.
Suggestion: Add more variants
These Ideas are mostly compatible with the 4PC server and I don’t know how they would work on reg chess games...
1: Spies; Pieces that are invisible to opponents. These are good for cat and mouse type games and Invasion ‘campaigns’.
2: Victory square; The same idea as KotH, but placed anywhere on the board. This is good for gauntlet type games.
3: Royalty blockade; an indestructible piece that the designated royalty can’t go through. 4B: Esquire or Chaperone; A piece that can be in the same square as the DR (designated royalty) and can escort the DR over royalty blockades. These are good for KotH/Victory Square or release the beast campaigns.
4: Neutral pieces; Similar to takeover, when you check the neutral king, all the neutral pieces become yours. When your opponent checks the neutral king, the pieces (regardless of whether you previously controlled them) become theirs. If nobody controls the neutral pieces, they remain as indestructible immovable pieces. If (in FFA) the one who controls the neutral pieces gets checkmated, all their pieces become neutral along with those already. 5B: The neutral king; moves as a rando-bot; cannot take other pieces; cannot get taken; cannot get KotH; cannot be checkmated; and never changes neutrality. These are good for games involving the concept of mercenaries or traitors. 5C: A takeover neutrality. When a color resigns or gets mated, all their pieces become neutral and you can only claim them one (maybe up to 8) at a time by landing next to them. Once controlled, they are yours until you lose or win.
5: Mud square; A square that instantly stops any piece that is not jumping over. At the next turn, you can move that piece regularly again unless hindered by another mud square. These would be good for guerrilla warfare games.
6: Teleporter; Like in the pac-man games, if you go through this you can continue out the designated other. Any pieces that only move one square at a time or only jump cannot go through these. These are good for Infiltration games.
7: lease bring Atomic chess to the 4pc server or at least atomic pieceS.
8: lease add unbalanced teams (2v1 or 3v1) as an option.
9: lease add an option that (in a team game) makes the winning team checkmate both players.
10: King Grasshopper or Cricket; A Grasshopper that has the additional movements of a king.
11: Backward Pawn; a pawn that moves backward. These are good for crunch games.
12: pope; a bishop and king combined.
13: I don’t know exactly how it would work, but I would like to see an immovable factory piece that spawns pawns or kings. This would be good for a robot apocalypse — Kill the factory, kill the bots it made
- Somehow most of the P’s got deleted, please give a shout out to which ideas you like the best and what you would change. I almost want to remove #6 and #13 because they go too far from the reg game.

All I want is the doubling cube for chess so that lost positions will be resigned instead of playing it out to the bitter end.

add RACING KINGS!
I will play this game every day on your site! At the moment, I do not play on this site at all.

Thanks to @martin_stahl [acknowledgments] I've just found this sub-forum for "Suggestion: Add more variants".My own suggestion now is the inclusion of the classical Los Alamos variant - which can be found at https://en.wikipedia.org/wiki/Los_Alamos_chess - as well as also the following further modifications of Los Alamos (i.e.: variants of the variant):
on 36 fields without Knights (instead of without Bishops),
on 36 fields without Rooks (instead of without Bishops),
on 6x8=48 fields without Bishops (like original Los Alamos but on a long board),
on 6x8=48 fields without Knights,
on 6x8=48 fields without Rooks,
on 7x7=49 fields without Queen.

add RACING KINGS!
I will play this game every day on your site! At the moment, I do not play on this site at all.
It was added
Lichess has more variants
Atomic Chess
Anti Chess
Horde
And
Monsters Chess
Transformers Chess