The following can be done after you lock Hollow Bastion.
Blaze Gem: Fat Bandit, Bandit (Agrabah, Cave of Wonders)
Blaze Shard: Red Nocturne (Monstro and possibly other worlds)
Bright Crystal: Defenders (Various places; Traverse Town Hotel has about 6 in the 3rd district)
Bright Gem: Search...