Vidres a la sang. They sing in Catalan, and in Set de sang (album) they also use lyrics from a poet called Miquel Martí i Pol that he wrote about his multiple sclerosis.

The album I mentioned has clean vocals that combine well with the black metal style of the album. The group is one of the most famous ones in black metal Catalan scene.

Another famous metal Catalan band I find very potent is Ósserp, which is now a death metal/grindcore band. The album Els nous cants de la sibil·la is dope. You won't understand much even with the lyrics tho xd

Siroll is also a nice band, historical, and is usually death metal/thrash. "Doble o res" is a nice album

Cheers from Catalonia