Aries - Undyne
Taurus - Toriel
Gemini - Muffet
Cancer - Asgore
Leo - Flowey/Asriel and Temmie
Virgo - Alphy
Libra - Monster Kid
Scorpio - Mettaton
Sagittarius - Papyrus
Capricorn - Sans
Aquarius - Chara
Pisces - Napstablook
Capricorn/Aquarius cusp - Gaster