Most girls claim that they are still only friends with their ex, but that rarely happens in reality. Of course, if they have broken up recently, they might still have some unfinished business so that you can trust her. Also, if they have kids, it's a different issue altogether, since they have to communicate with each other to decide when their children should visit their mother and their father. But that should be the only reason why she has his number. Of course, it's possible that she just forgot to delete his number, but that will plant the seed of doubt in your mind.
2 Your ex-girlfriend
This is even more disturbing than having her ex's number. Why would she have your ex-girlfriends number? It is possible that they are close friends, and if that turns out to be true, you need to back out immediately. In case, they are not friends; you need to find out how they became friends. Also, they probably discuss about you only, which is annoying.
3 Rays Pizza
There is definitely something fishy going on. You know very well that she never preferred pizza and on top of that, you have never heard about this place called the Rays Pizza. In most cases, it turns out that this is some person she is close with and doesn't want you to find out, so she used a fake name. However, it is possible that it is a pizza place, but still, you need to sure that she isn't doing anything behind your back.
This one is a bit different. Of course, it's not wrong to visit a psychiatrist, in fact, it's actually great that she has acknowledged her problem and is trying to solve it. But there are chances that she is crazy. You probably should try to check her medicines if you see this number, and be sure.
5 Your parents
Theres nothing wrong if your girl often communicates with your parents. But she probably doesn't need their number for that. She can talk with them on various occasions, and if she wants to talk with them, she should ask you to call them. A major possibility is that your mother and your girlfriend have become close friends and she is often sharing certain secrets with her which definitely should have never been revealed. Of course, when you are married, these facts don't apply, but for the time being, you probably don't want to see their number on her phone.
6 555 numbers
This is the strangest of them all. Phone numbers in the earlier movies all used to start with the area code 555. If you find such numbers in her phone, she probably isn't sane, or maybe she is from a parallel universe. You probably don't want to know the actual reason.
7 Your roommate
This one has no logical reason. Why would your girlfriend have your roommates phone number? They barely know each other and only talk when she comes to your house. This one will continue to disturb you for a long time, so it's better just to ask her the reason. Obviously, you should just hope that this never happens to you.
8 Your best friend
This could be either weird or fine depending upon who your best friend is. If your best friends is a female, things are probably fine, although she might be revealing several secrets about you. And if he is a male, then things might go wrong. In the end, you might lose both your girlfriend and your best friend.
9 Your brother
This is even weirder than having your parents numbers. To be honest, she should only talk to him at various events and not chat with him on the phone. If she wants to talk with him, she should ask you to ring him up. You don't want this to happen to you.
10 Your boss
There is only one logical reason why she should have your boss's number, and that is you both work for the same company under the same boss. If that is not the case, it is also possible that she wants to join your company and surprise you, but chances of that happening are minuscule. If you find out that she tried to talk to your boss about you, irrespective of what they talked about, you should immediately break up. Otherwise, you might end up in big trouble.