For young adults, 'They Both Die at the End' by Adam Silvera is quite popular. While not strictly focused on LGBT themes throughout, it has a main character who is gay and the story deals with love and mortality. 'The Gentleman's Guide to Vice and Virtue' by Mackenzi Lee also features a bisexual main character and is an adventurous and fun read that young adults would enjoy.
One top LGBT fiction book for young adults is 'I'll Give You the Sun' by Jandy Nelson. It has a complex narrative with elements of family, art, and same - sex love. The story is told from the perspectives of two siblings, one of whom is gay. It's a beautifully written book that can resonate with young adults as they explore their own identities and relationships.
Sure. 'Heartstopper' by Alice Oseman is a great choice. It's a sweet and heartwarming story of two boys falling in love in high school. Another one is 'Simon vs. the Homo Sapiens Agenda' which was later adapted into the movie 'Love, Simon'. It's about a closeted gay teen trying to navigate high school while also dealing with his identity.