The disclosure relates, in some aspects, to adeno-associated virus capsid proteins isolated from an in vivo library and recombinant adeno-associated viruses (rAAVs) comprising the same. In some aspects, the disclosure relates to isolated nucleic acids encoding AAV capsid proteins isolated from an in vivo library. In some embodiments, rAAVs and compositions described by the disclosure are useful for delivery of one or more transgenes to the muscle-tissue of a subject.