What Non-D&D Would You Use For A Dungeon Focused Campaign

[Reynard]

Worlds Without Number (very different system than D&D IMO)

Yeah, the Without Numbers games are superficially "OSR" ish, but I do think they count as very different from D&D-likes.

 

[Parmandur]

I've heard very good things about Torchbearer, from @pemerton especially.

 

[thullgrim]

I like GURPS for dungeon crawling, especially requiring resource management. You can make it as mechanically heavy or light as you want.

 

[schneeland]

I'm not sure if DCC would still be consider too D&Dish (I would understand if it was), but if it's not, that would be my first choice.
Second choice would be Forbidden Lands - although I find it to excel for overland travel and exploration, I think the dungeon part should still be fine.
Third choice would be Trophy Gold, which I want to try for something like this for quite a while, but never really get to it.

 

[John Dallman]

GURPS Dungeon Fantasy. It works well, and our GM was able to translate Pathfinder 1e scenarios on the fly without difficulty.

 

[pawsplay]

Dungeon Fantasy, or its older cousin, GURPS Dungeon Fantasy, is designed for this. I have some criticisms about the writing style and some of the aesthetics, but the engine definitely runs. Lots of weird creatures. Cool PC templates. Tons of weapons.

Dragonbane.

Honestly, a lot of the games I play otherwise have elements that are extraneous to this play style.