Eye of the Beholder (which was the inspiration for Legend of Grimrock) It's graphics are rather dated though

Yeah I posted this question on steam to and got EotB recommended there also, and Ultima Underworld.
If you've played Underworld which would you recommend the most?

I haven't played UU so I can't comment

You could try the game Starcrawler. Made in the same engine with the same first person group although the combat is turn based and it is science fiction instead of this.

So are there any puzzles in Starcrawlers? Or is it more of a dungeon crawler focused only on combat?

I'd say it is half puzzle. They have puzzle cyper stuff, push different buttons, etc.

Consider looking into Vaporum. It trades off the fantasy setting for something more steampunk, however. StarCrawlers was made in Unity, Grimrock was not.

Lands of Lore: The Throne of Chaos was kind of the culmination of the grid crawler back in the 90s. It’s a really good game that I would recommend. Keep a cluebook handy.

LOG is imho based on "Dungeon Master" by FTL, first released in 1987.
DM has a sequel called "Chaos Strikes Back" which is much harder in terms of puzzles and foes.
Also, there is "Dungeon Master 2" - which adds merchants where you buy/bargain and sell things.

Then there are games like the "Eye of the Beholder" series by Westwood (EOB3 was done by SSI and is imho not as good).

Then there's "Lands of Lore" (also by Westwood and the "secret Eye of the Beholder 2 successor".

"Black Crypt" is also a grid-based dungeon crawler I liked very much.

If you like turn-based RPGs too, you could throw a glance at "Wizardry 6" and 7 or "Might & Magic" 3-5 and "Might & Magic X: Legacy".

While those are mostly pretty old games, you can check out "Vaporum" and "Vaporum Lockdown" which are also related to LOG and the others.

The only other game that is somewhat similar is the Bard's tale series and also Might and Magic X

Try "Anvil of Dawn" or both of the "Vaporum" titles.

While not without its flaws, Lords of Xulima also has some dungeons with puzzles.

Late reply, but:

Operencia: The Stolen Sun is another recent dungeon crawler.

Vaporum, The Quest, Heroes of the Monkey Tavern.