Not really, but if you want hats you can get them in elemental gates, shops and if you transfer them from the older games into Trap Team, which is a REALLY dumb idea IMO. BUT you can unlock the Light and Dark skylanders in your collection if you put any Light or Dark object on/in the portal.
Edited 1 time - Last edited at 11:17:11 04/04/2015 by Deja Vu
well the 4 items you listed are all you need to unlock every level. but to get all the hats you need a trap master of each element. And i think a few are locked up in villain quests as well, so one trap of each element just to be safe.