I've not paid close enough attention to know which tracks were the first in the style.
I can just tell you the tracks or albums that changed my view on music & shifted my own liking!
Genetic - Trancemission was the first track that got me into the scene proper after being teased by what I'm sure was The Green Nuns' Optimum Creakage but never got confirmed. Sounded like it but I was trollyed so I can't be sure.
Hallucinogen - Twisted brought me deep in
V/A - Singularity shifted my taste into darker less melody driven music
Planet BEN - Silver made me fall in love with minimal
Butterfly Dawn is the CD I attribute my love of chill from stemming from!
Individual tracks I can't really think off & genre defining could be different for each person. I can only give my personal feelings here