At the end of your turn, if you have 5 or more cards in hand, discard your hand
Some cards are on the warning side of prices, though, so here are some suggestions
Rishkar, Peema Renegade is a great way to add +1/+1 counters to backup creatures that gave their counters away, and it grants all the creatures with +1/+1 counters the ability to tap for a green mana, which can lead to a big, explosive turn
House, President and CEO Overseer of Vault 76 Paladin Elizabeth Taggerdy Powder Ganger Ruthless Radrat Thrill-Kill Disciple Yes Man, Personal Securitron Desdemona, Freedom's Edge Keeper of the Accord Legate Lanius, Caesar's Ace Mysterious Stranger Pitiless Plunderer Rose, Cutthroat Raider Sierra, Nuka's Biggest Fan Wasteland Raider White Glove Gourmand Captain of the Watch Instant (7) Secure the Wastes Deadly Dispute Anguished Unmaking Wear / Tear Entrapment Maneuver Lethal Scheme V.A.T.S
A mix of both is certainly crucial to supporting decks with needy mana requirements