The Ratchet & Clank comic is by the writer of the games and is canon. It goes before All 4 One and sets up stuff that happens in that game, but it's not like you need to play that one to enjoy it.
The Sonic comics are a clusterfuck that are nothing like the games, but the first Sonic and Mega Man crossover, Worlds Collide, actually is like the games. It specifically rewrites history for that one arc so that it takes place in the games' world instead of the comics' world. It's also a generally great comic, and as great a crossover as you could hope for between these two series.
Digimon Adventure V-Tamer 01 is great, and everything in Digimon is canon, so this is canon to the games.
Ultimate Spider-Man takes place in the Ultimate Marvel comics universe. So there's all of those to read as backstory to the game.