MARIO BROS.
A-OK Wear, DX POW Gloves, and DX POW Boots for one (likely Mario) and Master Wear ("A" Rank every Cholesteroad challenge), No-touch Socks (dropped by POW Pep and SPEED Pep in the Energy Hold), and Tight Belt for the other (likely Luigi).

BOWSER
King Shell ("A" Rank every Broque Madame massage) or Ironclad Shell (Cavi Cape once you can use Spike Ball), Intruder Fangs, and either Power Band +, Economy Ring, or Heroic Ring.

Mix and match equipment for better results (such as Drumstick Ring with either Bone Fangs or Stamina Band for random auto-Drumstick eating plus DEF/POW Boost status when a Drumstick is eaten).