EVA foam floor mats.
Craft foam IS the same thing as EVA foam, just different names. But notably craft foam typically refers to thin 8mm and less sheets. You can by 1/8-1/2 inch thick floor mats that are much more durable.
With the exception of three of these suits (the Mk6 variant for Halo fans) and most of the helmets, these are made out of EVA foam.
This YouTube playlist can get you started: