Greyhawk, ....
Have you looked at the early Greyhawk modules and supplements? Or the 2e Greyhawk modules/supplements.
They are absolutely PACKED with magic items and mid/ high level NPCs.
Plus quasi Dietes, demigods and even greater gods are on the table for the PCs to encounter.
I love Greyhawk, but I would never characterize it as a low or even mid magic setting!