Idea is taken from the battle chess game.
Play normal chess. When piece A takes piece B, the two players play a street fighter (or whatever fighting game) match. The defender can only move or block for the first 30sec of the match. Whoever loses the match loses the piece. King doesn't fight, automatically wins if taking a piece, but you ...
This sounds similar to a variant from the Netherlands known as Paco Ŝako ("peace chess"). In Paco Ŝako captured pieces are not removed from the board; instead, they become "merged" and occupy the same square. Merged pieces move as a unit according to the rules for the current player's piece, and cannot capture. However, they can be captured, in which case ...
For kids younger than 6, you could try the following:
You start by a specific number of pieces(no pawns or kings) on the board mixed.
One piece is "it" and this piece "chases/attacks" the other pieces.
All the other pieces try to "run away" from this piece.
If "it" captures a piece, the latter piece is "it"
The players switch when a piece ...
Appart from the games you can find under https://bit.ly/PreChessGames (translated web for https://www.ajedrezparalaconvivencia.edu.uy/preajedrez) I may add these:
Chess with cards
You may want to try as well chess with cards. You can download the cards and print them.
Each player has a pile of these cards front face down, and they have to get one card, ...
Ralph Betza has a series of "crowd" games, but they don't quite match what you have in mind. The closest is the note in "Multiple Occupancy Miscellany", section "Crowd Capture":
What happens when you make a capturing move that ends on a square where there is more than one enemy piece? Many rules are possible.
The simple cases are that you capture