Perhaps i'm taking liberties with "a few years" but if you're interested go back to some old AIF, notably goblinboy stuff and remember when games where games not just VN's, graphics are antiquated by modern standards but worth it IMO, if you haven't go play "last horizon" by goblin boy, then when you're done replay it and be confused by the game changing while you weren't looking, the game itself stands up better than modern games of a comparable size IMO.
As for modern classics there are a few that come to mid for different reasons:
- Dreams of Desire by lewdlab, not because it's exceptionally good but it is a classic now, it was one of the forerunners of the incest boom and has to answer for a lot of tropes for that particular fetish becoming cemented around that time.
- Depraved awakening by Phillygames, well worth it for the combination of good story, renders and quality sex scenes. While each of these elements alone is good it's rare to see them all in one place, also plenty of replay value to get all scenes and endings.
- Acting Lessons by DrPinkCake, while i'm less of a fan of this as time goes by it is worth a look if you haven't, the renders are great, Liam is the best male NPC I've seen so far, melodrama gets a little cheesy for me at some points but it's still damn good.
- DanielsK's back catalogue, not all to my taste but the guy is consistent and it's nice to see how far he's come to get to Pine Falls (unfinished, currently in development but worth it).
- The Last Sovereign by Sierra Lee, it's all text based but the story blows 90% of games clean out of the water, yes games not just adult games, really even if you don't get beyond the intro it's still worth it, you won't see the twists coming, special mention for such classy content as the succubus "qum d'ump" who to be fair is the comedic support.
Honestly i'm not sure if you just want finished games because a few have been under development for over a year and have come a long way in that time but are as yet unfinished, things like long live the princess by Belle, I've been following that one since 0.2 and it's on version 25 or something crazy now. What i'm getting at is go have a look to see if anything that you played and liked a year ago is still being made, it's always a pleasant to find an "old" game is still being worked on.