The word 'popular' is always a tricky one Greenie, because it means different things to different people. For instance, if you are judging popular rave tracks in terms of chart success, then 1989 is a barren year - not one rave track made the Number One slot in that year. So, if you can narrow down the field of choice a little, I'm sure someone who visits this section can supply you with some more information, so please re-post to the Answerbank.
im not sure if these tracks were out in 89, but try: LFO by LFO; What Time is Love by KLF; and Humanoid by Stakker. Stuff by 808 state and Altern 8 are typical early UK rave tracks. The whistle song by frankie knuckles is reckoned to one of the most important tunes.