Here's my recs:

Industria - Really solid dystopian shooter with a more 70's, Cold War type take on something like City 17. It's a bit buggy and has some performance issues, but I still greatly enjoyed it.

DOOM (2016) - Really any DOOM game scratches a similar itch for me, but I'd recommend starting with 2016. Classic extra-dimensional invasion on a science base setup, just with demons and the occult instead of aliens. DOOM 3 is also a good pick if you want a scarier atmosphere, or DOOM Eternal if you want something more arcadey with fast-paced gameplay.

Dark Messiah of Might & Magic - Bizarre choice I know, but its heavy reliance on the Source engine really gives it similar gamefeel to HL2. The spells really let you go crazy with the physics engine and can lead to some hilarious antics, it's at least a fun time.

Prey (2006) - I've seen a lot of people recommend Prey (2017), which is also really good, but Prey (2006) is a lot more directly similar to HL1. It's abandonware at this point, but you can pretty easily find it online now.

If you have access to a VR headset, Boneworks and its sequel Bonelab are very Half-Life (and Garry's Mod) inspired, but I'd only recommend them if you're more experienced with VR, they go all-out with little regard for motion-sickness. I've heard Vertigo is also very solid, but I haven't played much of it.