Invent your own chess variant.

Ok, here's another made-up variant from me. I call it the Infinite plane chaturanga.  The pieces on ranks 1 & 8(grey and borwn squares) are the same as in the original chaturanga,  pawns promote to a ferz on ranks 8 and 1 respectively, but in addition there are some other pieces.  2 rows behind the 1st rank there's prince (6 of them), that promotes to a queen on the 8th rank, on the next row from the middle outwards there's alfil from shatranj (promotes to a grasshopper on the 8th rank), wazir (promotes to a pasha on the 8th rank) and archer (promotes to a demi-amazon on the 8th rank), 2 of each.  Now the old historic chess is getting funnier, eh? 

Pay a rent chess. Same board move and rules like a standard chess but with a twist.

They start with 21 token. Each player starts with placing Two type of payment square tile in the board. Diagonal tile and Orthogonal tile. There are 32 diagonal tile and 32 orthogonal tile. They can place them turn by turn whatever they want to wherever they want to place. Tiles cannot be stacked. Then they are going to place the pieces like the standard chess.

If the player who place a piece diagonally to the diagonal tile will pay twice to his/her opponent the number of squares the piece move. If not, he/she will only pay the the regular number of square. The same rules applies to orthogonal tile. The one who have no resource to play or checkmated lose the game.

Knight moves are one diagonal and one orthogonal so the player who plays a knight always pay 3 token. Castling is equivalent to 2 orthogonal squares and the square landed by the king is the tile to rent added 2 orthogonal squares for the rook at the kingside or 3 orthogonal squares on the queenside and the square landed by the rook is the tiled to rent.

Here's another one from me.  I call it "Magic pawns".   In this game there's only one royal piece (king or whatever ) and its sidekick, and the rest of the army are just pawns.  However, these pawns can promote to all the orthodox chess pieces, as well as historic and fairy pieces (see full list of fairy chess pieces in wikipedia), basically, they can promote to anything except for the selected  royal piece.  The sidekick isn't royal, so pawns can promote to it.  The goal is to capture/checkmate the opponent's leader or to bring your leader to the win square (the opponent's leader starting position).  In this example amazon (right) is the royal piece, and demi-amazon (left) is its sidekick.  The promotion ranks are 7th for white and 8th for black.  For a quicker game pawns may be replaced with torpedo pawns, or the board size may be smaller.   There may also be additional rules to make the game not so easy-peasy, for example, you can't promote to the same piece twice, or you can't promote to the same pieces as the opponent (for instance, if your opponent has promoted to a queen, you can't have a queen), etc.  Or players may agree in the beginning who can promote to which pieces.

And in this variant pawns can promote to anything - you name it - BUT the pieces on board

I've just invented my own chess piece. I call it the Gainer.  Initially the Gainer only has the power of a foot soldier (Japanese pawn), but whenever it captures, it also gains the power of the captured piece.  So, if,for example, the Gainer captures a knight, a rook, and a bishop, it will have the power of all 3, and it will turn into amazon.  If it captures a pawn, it will have the power to capture 1 square diagonally and en passant (not just pawns but anything, any number of times).  I wishI could materialize the idea on my tablet...

I have a suggestion. I think this will be suitable with a 10x10 board with other piece in other chess variant like chancellor and a pope and your so called Gainer will be place in front of the pawn. If it is behind the pawn, these pieces are too overpowered I think. Besides, they are the weakest piece at the opening phase and it makes the game more dynamic if they are in the front row.

Maybe.  Or perhaps we could give the piece more initial power, like a sergeant or a forward king for example.

Sorry but in my opinion, giving them more initial power will break the balance between positional and dynamic play.

Ok,  here's 2 more ( I think that would be fun on a very large or infinite board) the Pooper and the Janitor.

First, about the pooper.  It's a piece that can move in all possible ways (like any of the orthodox or fairy pieces), but it can't capture.  However, it "ppops" on its destination squares, so the enemy pieces  can't move there afrterward (or they will be gone)  until those squares are cleaned by a janitor.  Also, queens, rooks, and bishops can't move through squares that got pooped by the enemy.  A pooper can be captured, however, in this case, the capturing piece will be gone too (unless that piece is a janitor).  A pooper can't give a check or a checkmate, but it can crap all around the opposing king, so it is easier to checkmate it.

Now the janitor.  Like a pooper it can move in all possible ways, and it has the opposite function - it cleans the destination squares.  It cannot capture anything except the enemy pooper.  If there are only kings, and poopers or janitors left on board, the game is drawn.

Also there maybe a piece that combines these 2, called Janipooper (or Janiper?).  It poops for the enemy pieces and cleans for its own.

That would be great... How many of those pieces are on the board? Those pieces will make move restrictions given that there are many powerful pieces in the board.

I have a recent update to Pay a rent chess variant. Instead of turn by turn placement of tiles. I made a map suitable for the gameplay. The squares where the bishops are placed are diagonal tiles while the squares where the rook are place are orthogonal tiles.

How is this going to work?  One side plays with bishops, the other plays with rooks, and the goal is to eliminate?

Sorry i dont know how to draw orthogonal and diagonal tiles thats why i represent those pieces only as their representative tiles but not pieces.

How about a random symmetrical opening variant

So many different starting positions.

Basically both players have random pawn starts

Like this

This is one of the starting positions of many.

I think 1 each would be enough.  Also, pawns could be promoted to them.

Bullet chess but each player only has a king. You start with 30 seconds and win by timing out your opponent. There is no draw by repetition, and the fifty-move rule doesn't apply.

"TKO chess":

Legalize leaving the king in check or checkmate:  the game ends when a player actually captures the other king... if your opponent castles through check, you may 'en passant' capture their king.  😁

pawns can move backwards

Pawn back chess already exists.  At least in chess remix.