When a colleague's child turns 100 days old, if you are in the same department, or if you are not in the same department but have some interactions, it is better to give a gift. You may be able to ask for help from others in the future. It can also be regarded as building a social foundation for yourself, and let others see that you are humane.
You can give some children's toys, such as plush bears, big airplanes, cars, and various toys that develop intelligence, bells, cradle-style cribs, and cute baby carriages. These can be given to her children as gifts. If you are not in the same department and don't know each other well, it is better not to give gifts. In case others say you are being smart or something, it will be bad. Besides, there is no need to give a gift to someone you don't interact with very much. In short, you should be sensible when giving gifts. Give gifts if you need them, and save them if you don't need them.