Here is my idea for an interesting chess variant.

Allow the knights to move to any empty square on the board as long as they are not under attack and are not attacking anything on the square they "teleport" to.

This in addition to their normal move.

Thus on White's first move either of the white knights could teleport to all the squares on the third and fourth ranks that they cannot reach normally.

But not beyond the fourth rank as they would then be attacking Black's pawns. So it would be a restricted teleport ability.

What do you think?

That's cool, which reminds me I should dig out my old knightmare chess cards

Play a few games with a friend implementing that rule and you will see if it is interesting or not