Ill mostly avoid cards from un-sets or else most of the list would be jokes and puns
Tarrians SoulcleaverTarrians Soulcleaver, LashwritheLashwrithe, Blackblade ReforgedBlackblade Reforged, Wrecking Ball ArmWrecking Ball Arm, Thran Power SuitThran Power Suit, Cranial PlatingCranial Plating, and NettlecystNettlecyst beef up Kains power a significant amount and push him close to, if not well beyond commander damage range
This Duskmourn: House of Horror Death Toll Commander Deck includes 1 deck of 100 Magic cards (98 nonfoil cards and 2 Traditional Foil Borderless Legendary cards), 10 Archenemy cards, a 2-card Collector Booster Sample Pack (contains 1 Traditional Foil or nonfoil alt-border card of rarity Rare or higher and 1 Traditional Foil Uncommon card), 10 double-sided tokens, 1 deck box (can hold 100 sleeved cards), 1 Life Wheel, 1 strategy insert, and 1 reference card
If you want one for a deck (and you know you do, its even better than Doubling Season when it comes to planeswalkers) then I strongly advocate that you do so now
The final portion of design and start of development turned into set design
This is especially true with Alesha's growing statline that happens every time it attacks