Xeni by Rebekah Weatherspoon

One Kiss with a Rock Star by Amber Lin and Shari Slade

False Notes and Broken Frets by Elle Bennett

Sweethand by N.G. Peltier

Dare to Live, Dare to Love by Nicki C. Moon

Bonus: These are all adult, but in YA, try I’ll Be the One by Lyla Lee. Also, while not a Romance by genre definition, Verona Comics by Jennifer Dugan has a central m/f pairing and both are bi/pan

Double Bonus: While the (male) MC of The Girl Next Door by Amy Jo Cousins does not ID as bi (though the female love interest does), it would be safe to call him “heteroflexible”