ROCE stands for Roman's Own Chess Engine and the author states that it is yet another chess engine that probably no one needs, but adds that it's been a lot of fun for him working on it.
According to the author (Roman Hartmann) ROCE is a rather weak engine, but won't miss simple tactics. It will however play unsound moves in many situations. On the other hand it plays with a rather risky and attacking style and even mediocre players have a good chance to win or draw.
I read somewhere that ROCE is rated about 1880 in UCI Engines League and it's a very stable engine so it might make a good practice engine. I checked it out using Ftitz' Sparring Partner Mode with the engine moving fast on the "very hard" setting. I have to admit that in the first two games I played at lightning speed and lost due to some tactical oversights, so for the third game I had to slow down and actually spend a little time thinking and managed to win the following game.
Analyzing the game with Stockfish showed I actually made more mistakes than the engine though. But, just like in real games between humans, it was the last blunder that mattered. Anyway, it looks like this may be another of those unheralded engines that you might find useful for practice.