The latest development version of Stockfish is available at abrok.eu, and a good place to find engines is chess engine diary.

Hi, I would like to play versus chess engines. and I would like stockfish 15 to play versus chess engines.

Does anyone know where I can find chess engines to download? according to rating or whatever.

If your interested in the same thing I will tell  you what I have found.

lucas chess software has loads of engines to play against.
also the chessmaster software has personalities according to rating that you can play against.

thats about all I know.
I would like to play versus a 2500 engine to simulate playing a grandmaster.

If you know where I can download engines in bulk I would be able to upload them to my rybka aquarium and have engine matches where stockfish crushes everything.

Thanks.