I worked on and wrote a lot of material for a grimdark fantasy setting where this was essentially the case; arcane magic was more or less the process of warping the natural “background radiation” magic of the world to your own purposes, but to achieve that control, you needed to channel it through some kind of focus, and it turned out that due to Backstory Reasons, the best possible focus was basically human flesh. But said focus didn’t necessarily enjoy the “filtration” process of creating purified, easily controlled magic.
You could certainly craft magical staves from rare, magic-channeling materials, or brew alchemical potions with naturally quasi-magical plants, or even just wildly cast unfocused magic, if you really wanted to, but in the end, for the average wizard, filtering the wild magic through their own body was the best way to ensure good and predictable results that they could actually afford and use reliably, and doing so would slowly warp and wither them, leading most to an early death. . . and usually a closed-casket funeral.
Alas, I’m not published, and the last draft of the actual novel set there is hot garbage, so you’ll need to just content yourself with the above description for now :)
edit: there were lots of little tricks the wizards in the universe worked out, to the point of more or less carrying tanned leather waterskins full of, erm. . . extracted. . . blood on their person to use in a pinch, slowly boiling away the blood and dry-rotting the leather, necessitating an additional harvest eventually. The lead character was one of a handful of individuals who’d begun to master bardic magic, using song and sound to shape magic. While rarely as direct and potent as so-called blood magic, it could be surprisingly complex and multifaceted.