I would be interested in this discussion, as long as you will define "forgotten by everyone"?
If you actually mean "everyone" then statistically I'd say, "All of them".
If you mean "everyone in the IF-community" then I'm too out of touch to know, since I've been away for over a decade.
Which might give me a certain perspective. I suppose. I'm sure some of the classics I've completely missed in the last 14 years ish.
Here's a thread I found search "Interactive Fiction Classics"
I can personally still remember how Photopia changed my view of what IF was and how it revolutionized the "genre" so to speak. 3:05 also by Adam Cadre was super fun for me.
Andrew Plotkin's Shade is super hard but really cool, as was Spider and Web.
Galatea by Emily Short was enlightening.
What kind of IF do you like?
Lots of characters to interact with?
Role playing oriented?
What genres of fiction do you like?
Science Fiction (SF)?
Sci-Fi (anything that mixes SF with "supernatural")?
Slice of Life?
Philosophical (things that make you go, "hmm..")?