taquiones.net is a Fediverse instance that uses the ActivityPub protocol. In other words, users at this host can communicate with people that use software like Mastodon, Pleroma, Friendica, etc. all around the world.
This server runs the snac software and there is no automatic sign-up process.
https://www.carrodecombate.com/2020/09/27/directorio-de-moda-sostenible-en-espana/
No estoy seguro de si de verdad uno termina haciendo un bien al entorno (y a tu bolsillo) pero el directorio parece bastante completo.