I think its good to play three sometimes, mostly when your artifact count is looking low because of various colored cards in your deck, but I dont think Id ever play four again unless I was looking to build a dedicated swarm version
Thematically, some of them have abilities that play well with other cats, like lifegain and +1/+1 counters, while other legendary cats are off doing their own thing
The Top 32 looked as follows: 9 ABC 7 Metalfoes 5 Paleozoics 3 Mermail 3 Heroes 2 Yang Zing/Metalfoes 2 Darklords 1 Blue-Eyes After 14 rounds of action suddenly Paleozoic stood out at the top, in the Top 4 the deck was represented twice while ABC and Metalfoes scored one slot each
How does a Goblin come to acquire a Serra Angel skull
[L] Static Shock: 30 damage
But for others, kidnapping is an option too, as the lore of Homelands teaches us