Links for some of my favorite tutorials on patterning and EVA foam. Also at the bottom are some decent places to find large amounts of foam, foam clay, and even EVA foam shapes like cones and dowels.
You can also buy these things on Amazon, Walmart and other main stream online superstores.
If you aren’t a huge fan of freehanding your own pattern, or maybe you’re not confident in yourself yet, check out iWood Cosplay Kinpatsu Cosplay or Kamui Cosplay for some quality patterns and other products!
All around good info:
Links to some very helpful tutorials, blogs, and at the bottom where to purchase your thermoplastics! Keep in mind Michael's craft supply stores now stocks large and small rolls of Worbla, but they can still be found cheaper online.
All Around Good Info: