Cambridge Guitar Club
Here are ideas of music to play, with a guide to levels of difficulty eg. easy / intermediate / advanced.
Guitar Moment Volumes 1 to 4 (Guitar School of Iceland); collections of pieces by different composers. Easy to intermediate.
Guitarcosmos 1; (Reginald Smith Brindle, Schott); over 30 solos and 4 duos; tonal and atonal music from many styles including modern music. Easy to intermediate.
Folio for Guitar; (Ian Gammie, Corda Music CMP111); about 12 easy
duets and 18 easy solos.