Yarok, the Desecrated Yarok, the Desecrated is a value machine, doubling your enter the battlefield triggers and remember its any permanent, not just creatures, so abilities like Landfall will trigger an additional time too
It has a lot of partner commanders, which allow you to have two commanders instead of one
Paired with hyper-aggressive cards like Lilo, Making a Wish and Maleficent, Biding Her Time, Stitch, Rock Star can help you quickly create a board state that's almost impossible for your opponent to deal with
O'aka, Traveling Merchant* Trade that bead in for a card, knowledge for a touch of power is a powerful thing, especially with sagas, at a low cost
Here are a couple: Cyan: Vengeful Samurai is not an easy card to get out given his high cost of 7 Mana, but this can easily be brought down as this number is decreased by one for every creature in the Graveyard
What other collecting goals are you working on