I actually almost like this as much as Ertai Resurrected, but this does less--but also in simpler colors and cost
Hisuian Zoroark VSTAR, for instance, surrounded by Bidoofs
Vengevine A Vintage staple, Vengevine is a recursive beater with haste that springs back from the graveyard whenever you cast your second creature spell in a turn
Like Sauron, the Dark Lord, this card is best in the Commander format, where paying 5UBR is tough but managable and there are enemy commanders to trigger Sauron's second ability
Doubling effects are highly dangerous, because now every pump spell does double damage, and there may even be other things that can double the effect again
But why would you want to get life gain for your deck after having discussed how it is a dead resource unless you can abuse it