Speaking of #Quake , here is one of my all time favourite mods: https://www.quaddicted.com/reviews/oum.html
TBH, it took effort to find it — had I not been hung over from the New Year's celebration, I'd probably given up finding it as I've been certain it had a completely different name.
Anyway, the maps are super-neat with lots of detail, and it has atmosphere and somewhat vague, but a story — not unlike Zerstŏrer, but it's still in the vein of Quake.
And yes, of course it has new(-ish) monsters and weapons that are actually useful. And some new mechanics like those wall dispensers — no, not like in Half-Life! 😡
System Shock was first to introduce them — and relied on them heavily. Nothing original was introduces in HL. In fact, it gave me the first impression of being so unoriginal that I've given up on it almost immediately to play Shrak — another Quake mod that wasn't even that great when I look at it now. But it did have its fun parts.