With four creatures already in play, you can reduce Sprout Swarms mana cost to just one green mana
Lorcana (lore + arcana) is a magical realm where players take on the role of Illumineers and use magical ink to summon "Glimmers" (copies) of Disney characters from various stories, some familiar and some with bizarre twists, to help them collect lore (victory points)
If you'd rather have some less specific nonsense, however, then there is one other combo I found that involves all one-cost or less artifacts, creatures, or enchantments
Some guy just funded his whole wedding thanks to some Charizard cards after all
Decks that go wide benefit greatly from red enchantments like Purphoros, God of the Forge and other Impact Tremors variants
Cleansing Wildfire The trick with Cleansing Wildfire is to target an indestructible land you control, turning this into a Rampant Growth that cantrips