The precons have always been quite good decks
For example, Quantum RiddlerQuantum Riddler is a five-mana creature, but it can also be a two-mana one if you need to dig one card deeper or you meet the condition to refill your hand
Theres also Sylvan Tutor if youre looking for a weaker backup copy
Ideally, youd want to play both Jeskas Will and Dockside Extortionist in most red decks, then add additional red mana ramp cards as needed, but neither card is particularly cheap, so you might have to find some other cost-effective options in the interim
Yosei, the Morning Star - I don't like plans that intend to recur this, but Yosei is fine enough to Time Walk someone
Cards like Furnace of Rath, Dictate of the Twin Gods, Angrath's Marauders, Fiery Emancipation, and City on Fire double or triple damage output