Years ago I began dating a guy that I thought was too good to be true. So attentive, bright and fun. But every now and then when we would talk about things we had done or liked to do, he would start a sentence with the word "We..." and quickly correct himself by changing it to "I..." About the fourth time that happened, I asked, "Hey, are you married?" After a pause he answered, Well, yes and no..." I told him that the yes canceled out the no and that I needed him to take me home immediately. So, add those little slips of the tongue to the Red Flag list.

My red flag would be selfishness. If I note that she's completely self absorbed I run.

Theist

while dating tries to cut you off from friends and family.

If I've ever had a bad breakup, I don't remember it. I am good friends with both my ex wives. I can't think of an ex girlfriend or boyfriend I've had that I wouldn't hang out with platonically.

Never even considered that would be a red flag. In fact, if that's a problem... huge red flag.

You could add gaslighting. Gaslighting is a tactic in which a person or entity, in order to gain more power, makes a victim question their reality.
[psychologytoday.com]

In my opinion, there are many "users" too. Red flags are jumping from one relationship to the next to see what you can get. Being on the rebound without thinking things through can be toxic. I can usually tell if a person is sincere or not. It's just getting past all the smokescreens because people lie and tell lots of things until you get to the last push to get answers. They usually exhibit anger to stop the conversation. That's where the truth of what they are thinking usually lies.

All of the above are red flags!
Add:

1. Black and White thinking: See's individuals as all good or all bad and can switch back and forth.
2. Extreme emotions: Super Happy, Super Sad, Super mad, flips at the slightest trigger (sad and crying one second, Raging the next)
3. Revises Facts to fit feelings
4. I hate you/Don't Leave me
5. False allegations
6. Constantly have to prove your worth
7. Double Standards

8. Too many Texts/Calls often with long diatribes. Responses must be emmediate if not sooner.

9. Devalues others
10. Gaslighting
    ....to name a few others

Did you mean hovering? I wouldn't consider it abuse if my partner did all the hoovering. We have carpeted stairs and they're a pain to vacuum.

The Marine Corps flag is all red with a gold emblem and I am very proud to have been a member.

Any man who's used prostitutes.

I think it depends on the people and in hindsight, many things could be considered red flags.

It is stated that god comes first, also pets come first.

It's flattering at first, but quickly becomes unwanted.