I have two brothers and my husband has three sisters so that helped a lot. My kid brother and my husband's middle sister are my 1st daughter's Godparents. My kid brother was so excited, and takes it so seriously that he only wanted to be Godfather once. My first brother and my husband's eldest sister are my 2nd daughter's Godparents.
With my 3rd daughter it was harder. We wanted to make sure that family was still her Godparents, but it was very important to me that my best friend also be her Godmother. However my best friend is not Catholic. She was and is practicing in her denomination, so she was a Christian Witness for my daughter and my first brother is one of her Godfathers. We knew that could cause a problem on my in-law's side so we once again chose my husband's eldest sister as a Godmother plus her husband as a second Godfather. Her youngest child also has 4 Godparents so it wasn't really unusual for us to do the same. :-) And no one questioned us not using my husband's youngest sister at all.