Here is a fun idea for a Go variant:
On your turn, pass or choose any 2x2 area of the board containing at least one empty point. If you choose an area with exactly two empty points and those points are diagonally adjacent, place a stone of your color on exactly one of those points. Otherwise, place stones of your color on all empty points in the chosen area. Then perform captures as usual.
Otherwise, the rules are the same as in Go. Suicide is not allowed.