Fantasy novelists, as a collective, are probably the worst namers of characters you are likely to come across.
Why do we do it, and how do we come up with the names?
I think we choose names to make our worlds different, more exotic, more fantastical. To make it seem like somewhere else.
A fantasy with John and Sarah and Andrew as the main characters comes across as mundane. We are less likely to lose ourselves in the world that has been created because the characters are so ordinary. [This is not counting those fantasies that start in our world of course, and move over to the fantasy world in the course of the story.]
Names help us to create a sense of the world.
A world with names like Polgara and Belgarion (David Eddings, Belgariad) evokes a different world to one which contains Dutiful and Thick (Robin Hobb, Tawny Man series). This is different again to a world with Legolas and Galadriel (J. R. R. Tolkien, Lord of the Rings).
Some of us do go overboard with names. I have read novels where the names are all exotic and so similar that I have to keep re-reading sections to work out who is doing what.
You wonder how people come up with them. Maybe they make them up, or use fantasy name generators such as Rinkworks, Squid or Seventh Sanctum. (Seventh Sanctum also allows you to create planet, realms and tavern names.)
Others choose foreign names because they are exotic to us, in our own native language. You need to be careful with this, as a name that might sound foreign and exotic to you may be common in another language. I confess I like foreign names myself. I could populate a whole novel just with the names of people I work with.
Some authors name their characters after flora, fauna, seasons and so on. In that world, the fantasy equivalent of Peter might be Rock. Robin Hobb takes it a step further in the Tawny Man series with Dutiful and the like.
Mis-spelt names. Not quite a made-up name, because it has a phonetic equivalent. Carrell, for example, instead of Carol. (Carrell to me looks masculine. If I named a character in a novel Carrell, he would be male.)
Baby books are a source of inspiration, particularly for some of the older names that have fallen out of use. A quick look at Baby Names, under ‘M‘ gives me a list Magali, Maeryn, Maeve, Mahesa, Mahola, Mariska, Morella, Moss. I could keep going.
This begs another question. Should you be a language purist. Magali is French, Maeryn is Celtic, while Mahesa is Sanskrit. Can you put all three names into the same noevel?
Purists would say no, names in your world should sound as if they are the same language, which means you should base them on the same language too.
I’m not a purist. Yes, you probably shouldn’t have Angharad and Grr’chk as siblings, but outside of that almost anything goes for me.
I get my names from anywhere and everywhere. I’m not proud. Suri and Apple, by the way, both fit perfectly into a fantasy novel.