Belt, full set and item achievements still work. I think about half the other ones work. VIP achievement also works perfectly.
The ones that need you to win 500/1000 games, win 1000 games and win 5000 games work. I believe decap ones still work they're just hard as hell to get. Some of the ones like rising/falling star still work i think. Not 100% sure, I haven't seen anyone really actually get them recently.
The ones that require you to play 1000 games in a specific mod don't work at all, because the mods have been replaced/removed.
Some of them will come back one day, like lottery achievements might one day.
Others like, graduation ones, and events(LvP, clan leagues) will never be available again.
Then you have achievements like the OLDA one which is only given out to special people.
There isn't a full list of which ones work and which don't. If you want to see if an achievement is doable, you'll want to try to get it. If it requires you play multiple games of a mod, play that mod and see if it works.