Board Thread:Questions and Answers/@comment-24.34.155.154-20130608114715/@comment-14156117-20131228151825

There are two more aliens on that list

Clockwork: He was unlocked for 11-year-old Ben in Ben Again, but in the same episode, he was wiped from the Original Omnitrix

Articguana: Thought to be in the Original Omnitrix in Ben Again, but the only on-screen appearance of 11-year-old Articguana was The Ben 10: Omniverse video game