Themis (his aunt)--daughters/nieces Astraea, nymphs of Eridanos, Nemesis, Horae
Semi-Divine or mortal chicks he knocked up
Aegina (goat nymph)
Alcmene (wife of Amphitryon)
Antiope (river god daughter and Zeus' rape victim)
Anaxita (moth?)
Asterope aka Oceanid (wife of Endymion?)
Callisto (nymph changed to a bear)
Calyce (wife and/or mother of Aethlius)
Callirhoe (his niece)
Carme (Cretan spirit, daughter of Cassiopeia)
Cassiopeia (wife of King Phoenix)
Chaldene (a nymph)
Danaë (consort of Polydectes)
Dia (wife of Ixion)
Elara (princess, adulterous affair)
Electra (wife of Corythus)
Europa (Phoencian noble, raped by Zeus as a bull)
Eurymedousa (ant queen, raped by Zeus as an ant)
Euryodeia (immortal)
Io (his wife sister Hera's priestess, a young cow)
Divine dicks
Ganymede, divine youth from Troy
According to modern sources
You know, back in the old days, I really had a way with the ladies. Back then, if I wanted to pick up a woman, all I had to do was approach her in my aspect as a bull or swan, and she'd be all mine, helpless to resist. The move was pure gold. It never failed—even on goddesses.
But these modern women, that's a whole other story. For some reason, they just don't go for it at all.