Liver, Stigmata, Magic mush, The Halo, Sacred heart.
And one more I can't recall off the top of my head are good options.
Take those out of the boss item pool when isaac takes damage..
but then it's more of a penalty.
Also, most people learn that red health doesn't have any real upsides,
apart from renewability and it can ruin special room chances.

So, you're usually trading off:
renewability of red health (blood donation),
for:
mid-term security of soul hearts (devil/angel rooms)

What good players want is core stat ups.
shot speed, tears ups, damage and an average movement speed of 1.5 - 1.75
as well as good 'tear modifiers/tear proc effects'
I heard that Apple, Sinus infection and Loki's horn (singular) are spectacular oneshot fest ones.
And finally, is there a way to buff Crooked Pennie to give lucky coins or dimes, instead of just pennies, but only if it fails to double item pedestals? :3