[Savage]

In fact, looking at the list of gems, this could work. Time Gem, Space Gem, Soul Gem, Reality Gem, Power Gem, Mind Gem. 6 seems right for a lead-up with the last one maybe being found in The Avengers 2.

The Time Gem alone works for Captain America already. Could lead to getting Dugan in the modern world or The Red Skull or even screwing with time enough for Bucky to survive, unbeknownst to Cap.