I had a stuck gib-key. Nothing would move it. So, I wound up machining a jig that fit perfectly into the key-way. Then, I spotted and drilled a "pilot hole" in the jig, that would keep the drill bit perfectly centered in the jig, ergo also the key. A long drill bit of ~ 3/8 inch (I really don't remember) drilled it out. I saved that jig in the Listeroid "fix-it" box, just in case I needed it again.
I also hear tell from some sellers, that IF you heat the hub of the wheel up with a torch, you'll likely find success....never tried it. But next time, I might.