Ramp, ramp and ramp with benefits and card draw.
Here are more Commander-Deck ideas for the Ur-Dragon.
Lord Windgrace EDH Landfall
Lands in and out of your graveyard with kind of answering the most treats.
Here are more Commander-Deck ideas for the Planswalker Lord Windgrace.
Korvold EDH Sacrifice & Flexibility
Some removal, token-maker, aoe-sacrificing, very nice!
Here are more Commander-Deck ideas for the Dragon Korvold.
Abaddon EDH The unpredictable Outcome
Cast your own and your opponents spells from exile and cascade, plus some equipments.
Here are more Commander-Deck ideas for Abaddon, the Despoiler.