Some things that may draw you into specific colors are: A really strong rare you're excited about Plenty of "removal" cards that can deal with your opponent's creatures A lot of playable cards in that color A good "mana curve" in that colormeaning lots of creatures of different costs Ideally, the colors you pick will have all four of these criteria, but if two or three of those are true, that's plenty good
The First Chapter kicked off the story of Lorcana and established the context of a game of Lorcana, which features Disney characters in their classic form as well as radical reinventions
More recent Goblins lists have been more combo-oriented, relying on Wily Goblin to rush out Muxus even sooner
That can lead to some interesting surprises, because popular cards like Maze of Ith or Eater of the Death are considered true Uncommons of the set, which probably would nowadays be Rare
Ox of Agonas, Old One Eye, and Ebondeath, Dracolich require too many resources to want to regularly sacrifice to Carrion Feeder and other payoffs