Random useless post that no one asked for, alias, a couple of books for each ship I could thin of (ship as the main one, not just a side ship)!
Arthur/Guinevere: Sword at Sunset (Sutcliff), Queen of Camelot (McKenzie), Guinevere trilogy (Persia Woolley),
Firelord (Godwin)
Arthur/Lancelot: Knights of Camelot series (Luddington)
Arthur/Mordred: Mordred and the King (Culovich)
Arthur/Morgana: Firelord (Godwin), Morgana (Michel Rio), The Road to Avalon (Joan Wolf), Bedivere Book One (Wayne Wise), Camelot Lost (Jessica Bonito)
Bedivere/Guinevere: Sword at Sunset (Sutcliff)
Claudas/Lancelot: Laid to Ruin (Arden)
Gawain/Ragnelle: Gawain (Gwen Rowley)
Guinevere/Mordred: Mordred’s Curse (McDowell), Arthur the Bear of Britain (Frankland)
Guinevere/Lancelot: The Road to Avalon (Joan Wolf), The Once and Future King (White), Guinevere trilogy (Sharan Newman), Excalibur! (Gil Kane)
Igraine/Uther: Arthur series (Attanasio)
Lancelot/Elaine: Lancelot (Gwen Rowley)
Merlin/Nimue: Arthurian saga (Mary Stewart)
Mordred/Lancelot: Mordred Bastard son (Douglas Clegg),
Morgana/Lancelot: Mists of Avalon (Bradley)
Morgana/Vivian: Morgana (Michel Rio)
Arthurian Legends 