Oh, fun! I have quite a list.
I don't care for "made up" names. An example would be the names Jaden and Kaden. The worst is Braeden/Brayden. They are made up names based on Aiden. If you like that sound, why not just us the original name?
I'm also not a fan of names based on words for virtues. Faith, Hope, Charity, Grace, Patience, Prudence, etc.
I don't generally love place names used as names for people. Dakota, Brooklyn, Sierra, Madison, Savannah.
I never seem to love single syllable names. Chad, Todd, Grace, Jack, Ann, Grant.
I'm not a fan of trendy names, although I wouldn't let a sudden trend prevent me from using a name I really loved.
Names that sound whiny/nasally or annoying. At the risk of offending someone, here are some of my least-favorite names: Bryce, Blaine, Brian, Bruce, Ashlynn, Valerie, Jacqueline.
Finally, as a teacher I have a special list of names that have been ruined for me by bratty students over the years: Jordan, Eric/Erik, Penny, Brana, Aaron, Danny.