Queer Lit is an independent, LGBTQ+-focused bookshop based in Manchester, UK. They take suggestions on which books to stock up on (and are pretty fast on that trigger!), have regular sales, and offer a tbr-toppling selection of queer books. They've just opened their first physical store so if you can, pay them a visit!
Of all our guilds, Blackwell's is likely the most appropriate option for international book purchases. A UK-wide chain of independent bookshops, they offer a large range from academic to fiction, and are one of the best places to browse for indie (by independent publishers and self-published) books.
Bookshop.org is an online bookstore supporting indie sellers in the UK (there's a US version too). A % of each purchase made through the website goes towards a earning pool to be distributed among independent bookshops all over the UK, or you can choose a specific store to donate that % to.