Is there any position, where moving a pawn to last rank but not promoting it to any piece would be the best move?
By the way, I know this is an illegal move. Assume it is legal.
Edit: Now we have a nice answer from Dag Oskar which ends with stalemate. That's good. But I wonder, if there is winning position, winning by not promoting, and the only winning move is not promoting.
Edit #2: I think a winning position is impossible, as this seems to be occurable when opponent stalemates with promotion. If opponent is not stalemating, then there is no point of not promoting anyway. But if opponent stalemates with a knight, then bishop or rook doesn't stalemate, and etc. It's impossible to have a position where knight, bishop and rook stalemates. So, in every such position, there will be a correct promotion. Not promoting won't be the best move anyway.
Therefore, I'm accepting the answer.
Edit #3: Rosie F's answer demonstrates that it's possible to win with a 'not promoting move'. It's very entertaining to see it's possible. Thanks for the effort.