My dogs all had names when I got them but I didn't like any of them. Tilly's a rescue and was called Bonnie; I'd considered Tilly or Tess for her and she just looked like a Tillydog. There was no particular rhyme or reason to the name, it's a lot more 'usual' than my normal taste in dog names but I've just always liked it and it really suits her.
I got Rodaidh from his breeder at 6 months and he was being called Pickle which there wasn't a snowball's chance in hell of me keeping and if there was ever a dog that really didn't suit that name anyway it's Ro. I like Gaelic names and he is a Scottish dog; Rodaidh is a diminutive form of Ruairidh which means 'red king' so he's the 'red prince' and it's perfect for him. I adore his name and I've never met another dog with the same one. I often get told he should be called Aslan though because he looks like a lion.
Caoimhe was called Maisie when I got her at 5 months and it's just not to my taste, it's too girly. I wanted another Gaelic name, Irish this time as I'm Irish, and Caoimhe is a fairly common girls' name in Ireland - I found one of the 'names' Coke bottles with it on when I went home in May and bought it so I could prove to people over here that it is a real name
I know of one other dog called Caoimhe and spelled correctly although I've seen a few Anglicised versions of it - Keeva, Keava, Kiva etc.
I have a huge list of names for future dogs, I still love the name Tess but other than that they're pretty much all Gaelic.