Postprint biology repository
Many of the OSF preprints are postprints. OSF is a platform that unites several preprint servers, and the posting rules may vary from one provider to the other. You can check it here: https://osf.io/preprints/
Also, I can suggest checking individual servers. You can find a comprehensive community-curated list here: https://docs.google.com/spreadsheets/d/17RgfuQcGJHKSsSJwZZn0oiXAnimZu2sZsWp8Z6ZaYYo/edit#gid=0