D&D General Any suggestions for an approximately tier 3 level setting?

[werecorpse]

Can anyone suggest any published material I can use for a tier 3 setting, either wholly or to pick stuff from?

I have a long running campaign and the characters are strong 9th level characters and there are 8 of them. They are likely to end up on a different world for a while. An alternate prime plane rather than another plane in the multiverse. I expect the stay will be short but long enough for some adventures. When I look at most settings they seem designed for below 10th level which isn’t what I’m after.

 

[Eltab]

The 3e Forgotten Realms Campaign Guide ("The Book of 1001 Plot Hooks") includes dragons, demon lords, high-level spellcasters, kings / nobility, and similar foes that require high-level adventurers to deal with. You might find some ideas you want to develop further on your own.