Next I would consider stuff like Shamanic Revelation, Collective Unconscious, Freyalise, Llanowar's Fury, or maybe Inspiring Call if you'll be distributing enough +1/+1 counters to creatures
In theory, you can balance out the mana loss by playing two lands on the following turn, but if Zell gets removed youll be left down a land and in a very nasty spot
Lesson of the Divine on its own, allowed the tank to hold down an enemy for 2 turns for 0 mana and net 0 cards
The former card provides a unique case study to carefully watch over time: currently, the three-color Neon Ink version is the most valuable, but how long until it is reprinted with the latest foiling technique, in the rarest Collector Booster, with a serialized number denoting its scarcity
Since then, it seems that Rosewater or anyone else designing Magic have changed their minds on the matter as the only appearance of the mechanic since then has been on reprints of a single card
2 Apocalypse / Decree Of Annihilation / Devastation / Obliterate / Jokulhaups As the best wrath effects in Commander, all of the above cards have been piled together on this list