Then discard a card unless there are five or more mana values among cards in your graveyard
If you're looking for Commander decks built around gaining life, Id start with Orzhov, Esper, or Abzan
This is similar to Yu-Gi-Oh
Legendary 5Ds Decks - 1st
The cycle of Sword equipment is probably the most famous one and took decades to finish, having cards in Darksteel (2004), Scars of Mirrodin (2010), Mirrodin Besieged (2011), and even in Phyrexia: All Will Be One (2023)
(1/12/2024) Once you've announced that you're applying a card's dredge ability to replace a draw, players can't take any actions until you've put that card into your hand and milled cards