Are there any leather alternatives that do NOT use any plastic/petroleum?

I’m not against using leather itself, but the character I’m planning on cosplaying wears a lot of armor made from plants so I thought plant leather would be fitting :D

Unfortunately most plant-based leathers I’ve seen still have a good chunk of it be plastic-based. If I have to use plant based leather that still uses petroleum, I’d hope it to be 10% or under.

Even more unfortunately, is that a lot of the plant-based leather companies I’ve found do not sell sheets of their material. You have to contact them, which I’m assuming means they only sell wholesale. I do not need nor can afford wholesale amounts.

Is there anything close to what I desire? Or would I have to stick with petroleum-based plant leather or regular animal leather?