I have long lists of names too - especially for some of my mares that I stick with a theme or ones I come across that I like - many will never be used. Celena one of my mares most of her babies have - moon related names, her 1/2 sisters name is Etoile (French for star) many of her babies have star/celestial names in different languages.
Others just hit me right and the barn name - the horse names itself, why some of ours do not match the registered name at all. We have a Ninjas 45 Dreams (for her pedigree) her name, Dena. The mare I had foal tonight I call Muffy as her dam, Muffin, was here (I didn't own either at the time), and Muffy had no name, so I called her Muffy to keep track of her - her registered name Beach Bunny.
One of our babies born this year, Bonnie Fogg helped name (although she doesn't know it!). She was doing a reading on a different mare and said this mare thinks she's all that and a bag of chips! I thought that was a great name, so, Peanut's registered name is Shes All That!
I always liked what the Scheurings (Samis Lil Horse Ranch) do - all the names born in a specific year begin with the same letter of the alphabet.