Pianoteq has this simple but really nice feature, it uses an onscreen piano at the bottom of its window, very much like Renoise in the “Sample Keyzones” - except the velocity played is determined by the vertical position clicked on the keys. Click near the bottom, and you get a higher velocity. Click near the top of the keys, and you get softer velocity. (maybe flip this around so it would be consistent with the keyzone positions?)
This would be very practical in Renoise to fine-tune velocity sensitive instruments when you don’t have your midi controller handy =)