Beginning:
straight punches
round kicks
round kicks on the ground
getting up
Drill: Groups of 3, defender starts by punching to the pad non-stop, when the pad holder calls down, defender finds their way safely to the ground. 2nd pad holder comes in from behind and to the side to hold for a round kick, defender kicks, gets up and starts to punch again.

Intermediate:
Hook punch
uppercut punch
bearhug from the front arms free (neck leverage)
bearhug from behind, leverage on the finger
Drill: groups of 3, defender punches pad (or focus mitts) emphasis on hooks and uppercuts, 2nd attacker can either bearhug from front, or back, defender makes defense.

Advanced:
spinning heel kick
sliding def v. spinning heel kick
stopping def v. spinning heel kick
Overhead stick, left handed attacker
Drill: groups of 3, sparring with spinning kicks (along with everything else, or restrict combatives as applies to your class), 2nd attacker does overhead stick on the left side (include right side too for more advanced students).