Here are some random pre-draft workout videos posted by an obscure YouTube channel (maybe reposts, or old clips spliced together?):
Kuminga:
Bouknight (especially for kb02):
Scottie Barnes:
Jalen Johnson (my top pick by far at 9, although I expect he will go top 5 after workouts):
There are more to be found, but I don't want to spam the thread.
Personally I think Jalen Johnson's size, athleticism and skill set are way too tantalizing to pass on if he's there at 9, which I don't think he will be. He has all the attributes to be a big time player in the NBA.