WSIB All time classics like the half life series

I recently played Black Mesa which got me into the half life series and about a month later I have now played every valve released half life game and that got me wondering which games I missed out on back in the day.

Im 30 years old and used to play on the Xbox 360 and later the ps4. I now play on pc but usually go for games from the last 10 years.

What are some absolute must plays that still hold up to this day. I would like it to be a little bit faster paced in gameplay. I played through mass effect 1 and the Witcher 1 recently, and I liked them but the slow pacing and tons of dialogue didn't really hook me into playing the rest of them.

I already played the portal games (and probably a bunch of other recommendations) but I'd like to know if there's some I still haven't played for some reason!