1) She's on psychiatric medication. Doubly so if unprescribed.
2) Supports abortion, very vocally. Nutty way of saying she regrets hers. Misery loves company.
3) Lots of guy friends. All waiting in line, so to speak.
4) Still facebook friends with "exes" from said group of guys. They aren't exes, they're sexual spare tires.
5) Social pics of herself in skimpy clothes - even from back when she was supposedly "taken."
6) Claims to be sexual assault victim. Yes, even if true, a red flag.
7) Terrible credit rating. Bonus points if tied to worthless college degree with student debt.
8) Has an account with a sugar-daddy type app. As if dating apps weren't bad enough...
9) "Just got out of a bad relationship." Guess which one of them actually went bad?
10) Has ever done porn. Even if she sued the producer after being "tricked" etc
Most of these are not just "red flags" but absolutely obvious dealbreakers that you would either have to either be retarded or severely blinded by lust to ignore.
Just because a girl doesn't do porn or have a sugar daddy doesn't mean you should ignore "more subtle" red flags.
You point out some of these. Women who take psychiatric meds, support abortion, and have lots of male friend, for example.
I would add wearing makeup or otherwise feeling the need to alter appearance to be "sexier" as a red flag.
Also, I agree with EC that "hymen not intact" is enough of a red flag, with very few exceptions (such as a girl who has repented her sexual sins before God).
"Hymen not intact" extends to girls who are technically virgins but have done anal or oral, regularly watch porn or engage in solo sexual behavior, made out with a ton of guys, etc.