Yeah, it's kinda hard to confirm how many there will be for sure, unless I missed an announcement? Some have said there will be an Ocean Biome Boss, I dunno. The devs did also say awhile ago that all future dlc for the game will be free due to how popular the game is (how many copies of the game sold, etc.). All I see mentioned is the Mistlands Biome (boss), North pole (ice biome boss?), and the South pole (fire biome boss). I'm sure the north pole and south pole biomes have actual names to them but you get my meaning. But, not that I'm complaining at all, it would seem like Valheim could take...well, years to be a completed version. I've been playing Empirion since the beginning of 2016 and even though it's no longer early access, it's still being fleshed out.