If Gale is part of the party in Baldur's Gate 3, he'll constantly remind the protagonist that he wants to visit Sorcerous Sundries in Baldur's Gate. The shop has the best collection of tomes and magic scrolls north of Candlekeep, and aside from Gale's quest it's also home to the wizard who hired an adventuring party to find the Nightsong.
Baldur's Gate 3: Sorcerous Sundries Guide
There's lots to do and find in Sorcerous Sundries, the premier wizardry shop in Baldur's Gate.