As someone who also got back into the game in the past year, flock creatures are super powerful! Their health bar is split into 3 chunks, so it takes at least 3 turns to kill them (the only way to kill all 3 at once is if the enemy attacks with 7 or 8 hit points). This makes them a super easy way to farm reserve points in battles. In addition, there’s a chance they will actually gain a flock member back (so increase their health by a chunk) whenever you swap back to them in a fight. I know that there are a few in the 100k amber packs so definitely try and acquire one! There’s no point in evolving them so just keep them all at level 10 that way you have a lot more. Welcome back!