This is often referred to as a 0-card combo since you dont need to have any specific cards in your hand to power out a win
In standard it was the core to the aptly named Puresteel Paladin deck, using its main ability to draw into more action and later on the metalcraft ability to cheat out on some equip costs, but it has also seen play in Cheerios, a deck based around 0 mana artifacts and Paradoxical Outcome to eventually cast Grapeshot, and most recently in Hammer Time, which focuses on Colossus Hammer, where Puresteel Paladin once again comes in to both help circumvent equip costs
Bonehoard Dracosaur ($15.16) A big creature with evasion that also gives you a temporary hand advantage every time it attacks, Bonehoard Dracosaur doesn't simply bring a lot of value for its arguably expensive cost of 3RR
There is no shortage of fantastic planeswalkers such as Oko, Thief of Crowns, Teferi, Time Raveler, and Narset, Parter of Veils
For the classic mono-black swarm, Marrow-Gnawer (the iconic token doubler) or Karumonix (the budget pick)