What about 3 fold repetition?
Teamwork Chess

Overview
A game of Chess960 chess but the players work together to stalemate in 65 or under 65 moves.
Basic Rules
- 8 * 8 board
- Chess960 starting position
- Classic pieces
- Pawns promote on 8th rank
- Castling rules are normal
- En passant is allowed
Changes From Classic Chess
- Goal is to stalemate in 65 or under 65 moves
- Elo is the same for both players (If they fail to stalemate in 65 or under 65 moves, then they both lose
- 10 Elo. Same for vice versa.) *******Except for the situation shown with the Chess.com logo*******
- Elo always changes by 10. It either goes up 10 or down 10 but never changes by any number other than 10.
- You cannot draw by agreement
If a player resigns, then only the player who resigned loses 10 elo. The other player's elo stays the same as it was before.
Finishing Touches
- If the game ends in anything but stalemate (i.e. checkmate, perpetual check, etc.), or the game takes over 65 moves, then the game is considered lost and both players lose 10 Elo.
This is the end of my idea, and I really hope that you enjoy and want to make it a real variant.
Goodbye, and have fun playing chess! *SHOUTOUT TO @XXXIKKKKKKK*
--- @Sterling-Murphy
Someone else thought of chess 960 but I suggested not only that, but combining that with another seemingly rejected variant, making both good if they are together.

One issue I find is that it's only fun the first time. Once players figure out how to win, they'll just keep doing the same line over and over again, which gets boring.
Overview
A game of Chess960 chess but the players work together to stalemate in 65 or under 65 moves.
Basic Rules
Changes From Classic Chess
Finishing Touches
This is the end of my idea, and I really hope that you enjoy and want to make it a real variant.
Goodbye, and have fun playing chess! *SHOUTOUT TO @XXXIKKKKKKK*
--- @Sterling-Murphy