Anyone know where I can get a list of different core materials and their permeabilities?
Wikipedia has some (with footnote citations!)
The CRC Handbook probably has a table somewhere, too.
Go to the manufacturer's websites, and look at their core material datasheets.
Here's a link to the TDK pages, for example:
mag-inc and mecrometals will cover a broad range. You'll still need someone that sells laminates.
Separate names with a comma.