Any players left Bilbao?
Not many - though there is this right back from Bilbao Athletic without a club.
https://www.transfermarkt.com/markel-etxeberria/profil/spieler/212852
Was on loan and played 28 games for Real Valladolid in Segunda Division as they won promotion back to the La Liga.Actually last season played for CD Numancia, they made the playoffs but did not get promoted. Had played for Real Valladolid a season before.
I checked Real Sociedad players without contracts as well, but there were none that made sense.