BW2 Red Collection [Noble Victories in English] and BW4 Dark Rush [Dark Explorers in English] both dont exist in unlimited edition afaik
One obvious inclusion is the cycle of Court enchantments (Court of Ambition, etc.) that give you extra benefits when youre the monarch on your upkeep, but dont forget more common cards like Phyrexian Arena, Bitterblossom, or Twilight Prophet
Its also worth mentioning that there are quite a few cards that have pseudo-afterlife abilities
I have Omnath in a real life Commander brew built around Wildfire effects to ramp, drop him, Wildfire and keep what Elementals I dropped, and then if any died, I can use their death triggers to kill wounded stuff
Artifact Ramp (CTRL to add secondary) Removal Skyclave Apparition When this creature enters, exile up to one target nonland, nontoken permanent you don't control with mana value 4 or less
Having high efficiency and utility isn't that hard to find on a magic card but it is very hard to find on a card costing less than four mana