I must admit - I don't know the songs connected to the artists you mentioned - Gong, Japan, Tangerine Dream and Mike Oldfield. But, if they are in the broad genre of 80s synthpop, I would think that I heard songs from them before.
Again, in the broad genre of 80s synthpop, back in the day, I would hear songs like Yaz "Situation," Gary Numan "Cars" (although that was in the classic 80s movie Last American Virgin), and New Order "Blue Monday" - along with more pop mainstream synthpop songs.
Of course, now that I think about it, maybe the reason why I recognize these songs is that they are replayed on YouTube and the like, whereas songs that I might have only heard a couple times back in the 80s might be just completely forgotten for me.