Tolkein, as a young man falling in love with language, liked the euphonious sound of the words cellar door and because of that, when he wrote the Silmarillion in middle-age, he called one of the principal characters ‘Selador’.
If a character’s name doesn’t jump out at me as soon as I’ve shaped a character, I can agonise for months. I have to use a placeholder (TK = To Know) until the right name drops into view.
I’m pretty sure Jane Austen referred to the Gazetteer, a list of English towns, when she got stuck (Woodhouse, Thorpe, Bingley, Wickham).