Here are some extra ways to make more money: Treasure generators are separated into two groups: consistent and single use generators
Herald of the Arc Light Herald of the Arc Light is a Synchro 4 used a lot in Ritual decks, due to its effect of being sent to the graveyard
Modern Horizons cards making an appearance in this strategy are Sterling Grove, Enchantresss Presence, Solitary Confinement, Sythis, Harvests Hand and Sanctum Weaver, making this archetype the one that gained the most amount of cards in the format
Combined with Suspicious Food Tin, which heals 80 damage if you discard a Psychic Energy, and Mallow & Lana, which can switch + heal 120 damage, Gardevoir VMAX becomes a force to reckon with, capable of both aggressive damage and healing support
Sure it gets exiled after, but free is a deep discount and four mana for a large spell isnt anything to sneeze at either
If he has a gimmick that works with GY exclusion like Orphee and he SPYRAL, it's worth a look