Souls. See Blazblue, Devil May Cry, Bayonetta, Dark Souls and Demons' Souls for excellant opportunities to make the most out of human resources. And some superhuman, inhuman and subhuman resources.
Songstone, while not strictly speaking magic in the context of its own setting, is pretty much indistinguishable.
Lyrium-now in original flavour green and corruptive red versions thanks to Inquisition.
The Great Crystal from Crystal Chronicles, if you ever need to jerryrig a device to jettison negative human emotions into deep space. Just make sure you have a way to keep them from combining! You may also be interested in myrrh, which apparently boosts the crystals.
Thanks to Spyro, you yourself can become a magical resource with the right body perks.
Dust from RWBY has a variety of applications, not all of which are fully understood. Mainly the blasty smashy kind of magic though.
The Gulug Stone from FF9 takes this quite literally, with its primary effect being to store, release and deposit the ability to use magic in those nearby.
Mistborn has a variety of enchanted metals that are the basis of the local magic system, including one or two that are basically a god's remains.
FF14 is a goldmine for these though: Apart from the various Materias, there's Alexandrite for spiritual interference, Zodium for reinforcement of other materials and probably others we've overlooked.