I started a company creating affordable hydrofoils not too long ago. I have tried a bunch of different materials and shapes for the foils and currently working on a triangle version (I think it would be pretty suitable for efoils). Currently they are best suited for wakeboarding and kitesurfing, but planning on eventually getting into efoils.
Please, go to https://swefoils.com/ and let me know what you think. I am looking to send a hydrofoil to someone who has a lot more experience with foiling than I do (ideally in the Midwest) who would be willing to try it, and possibly be interested in installing an propeller to it. If you would be interested send me a message.
Note - I am not selling them yet and the website has a lot left content to be created, but I would appreciate any comments or ideas.