I use a dictionary. Best online sources for names are to Google baby names starting with D or go to Thesaurus.com and type in other words -- names of sires, etc. -- and you'll get all kinds of name ideas.
There's a lot of good D names. ;D I've been trying to use Z names since it's the Z year but I gave up! I had a Zelda but that's it. Z names are hard to think of!