One of my favorite cEDH commanders, Malcolm, Keen-Eyed Navigator is a solid little value engine by itself
After all, you get to choose which creature you kill with Terror, while your opponent chooses with Edict
These cards are instead expensive because of their extreme scarcity
1Ryusei, the Falling Star
Whispers of the Muse (T1, Ext, S, Block) A favorite in "Turbo Xerox" (a blue deck which used minimal land but a ton of cantrips to thin out the deck), Counter-Phoenix (Shard Phoenix + Forbid) and Tradewind-Awakening (put Awakening on the stack, tap all your lands for mana, untap all your lands), Whispers has what might seem like a hefty price to pay for one card but you get to do it turn after turn after turn