Lucas Chess is a free program for Windows which includes 36 engines with ratings ranging from 600 to 3000. It also has a bunch of tactical puzzles and training features.
https://www-lucaschess.rhcloud.com/
Nagaskaki is also free and for Windows, and has ten or so levels ranging from 1472-2300.
For iOS or Android, there is also Remi Coulon's The Chess Crazy Bishop which is free and has 100 levels ranging from 258-2300.
I should note that Stockfish (Smallchess), Lucas Chess and Chessmaster even when set at low levels will mix in stretches of extremely strong moves, and then throw in the occasional blunder which you have to spot. This is very different from playing against a human at that rating level. Humans play slightly weaker moves generally instead of alternating ultrastrong with ultraweak. An engine with a low base rating on CCRL won't be able to throw GM level moves at you although it will still likely be stronger tactically than a human with a similar rating. Shredder is perhaps better at maintaining a consistent level when you lower its Elo than some programs. Crazy Bishop seems pretty good at this too.