8 cards where the card is tagged “donate-mana”

Bigger on the Inside (Doctor Who #115)
Jetfire, Ingenious Scientist // Jetfire, Air Guardian (Transformers #3)
Jetfire, Ingenious Scientist // Jetfire, Air Guardian (Transformers #3)
Mad Science Fair Project (Unstable #154)
Mana Abundance (Mystery Booster Playtest Cards 2021 #58)
Spectral Searchlight (Commander Masters #411)
Stadium Vendors (Battlebond #63)
Valleymaker (Shadowmoor #221)
Victory Chimes (Commander 2021 #274)

The message was clear to Sorin—time to search for something else.