@kelly Yes! There is a long history of scratch DJs pressing/selling their own "battle records" or "scratch records" which are compilations of samples meant to be played at DJ battles, or as tools for other DJs.
Super Seal is one that I still own from my DJing days. You can listen to it linearly here, and you can hear that there is a "beep" cue before each sample begins to help the DJ.
@kelly you'll notice the samples gradually trigger faster and faster in "tempo". This is because they are locked to the radial angle of the record, so that if your needle skips and lands in an adjacent groove, you are probably still going to land at the same spot in the same sample!