Non-hell textures that look good in hell maps?

Hey, I'm working on a hell map for a project and I'm wondering what vanilla textures would work well with the current palette I have. I'm currently using reds and grays for textures, and some lava as well. 

Well... any texture can be made to work if used right. You only need to look at the iwads to see that. Are you sticking with only using reds and grays, or are you open to splashing in different stuff? Too much of the same palette can get tiring to the player, and sometimes lead to confusion.

i personally think that the most prominent texture on TNT, you know the one that almost made the whole map08: Metal, is a really versatile texture. Kinda brownish, but not too much. Or on the first tnt map, just turn around and you will see it.

I had seen it used on a vastly array of different situations: acompanying lava floors, around marble areas, as metal support along wood textures, on rock areas, sewer like areas, and a lot more.

That texture looks awesome everywhere.

I only wish there are more variants of it.

METAL1 (the hexagon shaped metal wall) would look good with a lava floor, and the metal hexagon shaped flat (i don't recall what's its actual name) as a ceiling on a hell map.

Obligatory green marble shoutout as OP had not mentioned it. But it contrasts against the red brick and ash textures nicely.

Doom’s Bookshelves and Hell maps seems to go together well!

GRAYDANG

The TEKWALL textures can work well in certain hell maps.

Any kind of brick and most kind of metals, including hexagons. Any kind of wood, even if not particularly hellish. Zimmer because what the hell is this, clearly it is from hell.

Compblue and the CEIL4s all add some striking contrast against the red brick textures that I reeeeeeally enjoy. Sladwall and Sladskull both fit well. Ickwall, when used well, can look great in hell but don’t overdo it! (Looking at you, Mt Pain. . .)

I get a lot of mileage out of METAL2-5 in Hell maps, good for a kind of gritty industrial look (referring mostly to a map I've just finished which tries for this kind of feel).  SPACEW3 (or whatever it's called, the dark one with all the CRT screens) as well.  The SLADWALL, TEKWALL, ICKWALL and PIPEWAL families can all also work great when used right.  A lot of the BRICK textures can look good too.  And then...well I forget the names of the two flats, but you know the ones, one is edged in metal and the other in wood but both have the same fluorescent lights behind a grate or whatever...anyway those look good in such Hell maps.  Also white striplights look awesome against green marble and don't let anyone tell you otherwise