Making this post so users can share information on cruelty-free clothing that is built to last.
Ideally this will mean both vegan and natural materials but I'm aware synthetics are near unavoidable. Please feel free to share synthetic materials that are made for long-term / indefinite use.
In summer I typically wear only cotton / linen but as the weather gets colder I'm looking for warm or waterproof winter clothes. I asked this question to a vegan community already and I'll put their responses in a comment below.
I use an "oilskin" (actually cotton) as a raincoat and wax it with a mixture of carnauba wax and jojoba oil. Castor would probably also work, you just need to add something to soften it that's heavy enough not to get displaced by water.