I tried playing Koumei Satou's wonderful Mistake of Pythagoras in Half-Life 2: VR... but then its scripting completely failed in the second map. Some incompatibility to do with running maps made in 2004 on Half-Life 2: VR's version of Source? My understanding is that there were a number of mapping functions which were deprecated in later engine versions.
Last year I played through Zebrajack's Pseudomod more or less without issue in Half-Life 2: VR, with the exception of one map running very poorly on my PC. I really liked Pseudomod - it felt to me like it shared the kind of sensibilities you'd see in a Half-Life 1 mod, namely an 'anything goes' tone of free-wheeling, playfully-written adventure, and it was kind of... wonderful to get to experience that, in VR, in 2023. Pseudomod also had a particularly tall ladder for me to climb, quite literally, and the mundanity of what I'm about to say may shock non-gamers, by hand.