Scud Fiber Materials (Patreon)

Fiber in the water is a slightly more... temporary material than it is on land (prone to melting and sliding apart) but it's still useful for various applications, eg kelp fiber mesh being used as substrate on which to quickly grow bioengineered corals for hard building materials and custom casings.

The glass blade shown here is likely volcanic glass, as glass work (like metal forging) or a dangerous new science that can only be accomplished on land.