What to say to your girlfriend, what they say
You can find a very cute name from cartoon characters you used to watch, toys and other fun stuff from childhood. Then there is your memorable times category. Now this is easy because you will simply have to remember a particularly lovely time together and take inspiration from there. For example, if you went to the park and she kept looking and touching the flowers, you can call her bumble bee. Another good source of inspiration and the most commonly used ones is food.