If you don't mind complicated designs...
Demon Crown from Cave Story, because duh
Lucca's from Chrono Trigger, because IIRC she's pretty cool and also Kirby needs a technology ability (aside from Laser and that crappy scanner from Super Star that doesn't count because it sucks)
Yuyuko Saigyouji's from Touhou, because her and Kirby have at least one major trait in common (plus it'd just be cute)
Demon Crown from Cave Story, because duh
Lucca's from Chrono Trigger, because IIRC she's pretty cool and also Kirby needs a technology ability (aside from Laser and that crappy scanner from Super Star that doesn't count because it sucks)
Yuyuko Saigyouji's from Touhou, because her and Kirby have at least one major trait in common (plus it'd just be cute)