videos in AudioSet
A list of about a million ten-second YouTube clips, each labelled with the sounds in it, that Google published in 2017. Labs use it to train and test general audio and music models.
Including EFM SCP5 freeware VSTi synthesizer (SCI Prophet 5 emulation), 1980's Retro Funk (KRM61 freeware VSTi synthesizer audio demo), VSTi Retro Wave / Synth Wave (SQ8L, U-NO-LX, FL Studio)