Updated: Aug 13, 2021
I'm going off my pre determined article schedule to post about this subject, because I really am excited about this and wanted to weigh in on this technique. In the past few years, we have seen the debut of pre-textured sheets of foam (from Yaya Han and Lumin's Workshop to name a few suppliers), and increasing tutorials on how to texture and detail foam by hand. Now, there are even more options when texturing foam, and depending on your resources, it can be arguably cheaper in the long run than purchasing foam rolls of textured foam, while also saving you time in texturing by hand.
Now to be completely transparent, this technique has been mostly used by the D&D miniatures community so a lot of the stamps and rolls you'll find will be for miniature buildings, or dioramas. However, the cosplay community seems to be integrating these techniques for themselves now.
Punished Props Academy recently came out with a line of texture stamp 3d files that you can print and use to texture your own foam. If you have access to your own 3d Printer this can be a huge budget friendly game changer. The file only costs $5 and includes the following textures:
Stylized Wood Grain
These stamps are excellent for small pieces of foam, which is great. Instead of purchasing a large piece of textured foam that you may not use in it's entirety, you can instead cut your pieces and then press it with the stamp.
You'll note that in the video they soak the piece of EVA in water prior to pressing with the stamp, This is a common tactic in embossing leathers as well. It helps the texture and shape of the form you're pressing into the material take. Thankfully you could use a book to press the stamp into your piece if you decide to go this route. You can also heat treat your foam and press the stamp (or roll) firmly to get a texture. Though it may not come out quite as vividly.
Punished Props' texture pack is hardly the only 3d model you can find online, but it is the only one made with cosplay armor in mind that I've found to date. You can find a few more low cost, or free, options here:
40x Texture rolls for large continuous patterns. Has mostly textures for D&D miniatures but a few textures that could be used for props or armor the reptile skin and woodgrain files are crazy amazing. - $5.04
Cobblestone Arches x 3
Cobblestone Arches Soft Round x 2
Cobblestone Squares x 4
Cracks x 4
Hexagon x 3
Roof Tile x 3
Skulls x 2
SquareTiles x 2
Strait Lines x 3
TreeBark x 2
WoodPlank x 4
Woven Bricks x 2
Wood Grain Stamp - Free
Diamond Texture Roller - Free
Set of Ten textured Rollers - Free
If you have access to, or own your own, 3d Printer this gives you the ability to resize the files as you need. It also affords you the luxury of being able to print them yourself and have them within the course of a few hours-days.
If you don't have access to your own 3d printer, you can easily upload the files you would like printed and order them through Treatstock (Which is my go to 3d printing service for pieces I cannot print on my own machine).
If you are working with small pieces of thin foam you can also use fondant presses to add texture to your build. I used a silicone petal mold to press texture into my LED flower project.
All in all this technique is super cool, sustainable and overall budget friendly especially if you make a lot of textured pieces for cosplay.