A very easy way is to name the child after a magician you especially admire, like Gerald (Gardner) or Phyllis (Seckler). These have the benefit of being largely normal names (thought some, like Phyllis, are still sort of outdated) means that they will probably never cause your child any sort of problem with spelling or discrimination. Plus, so long as the child and those close to him or her understand that "Gerald" is an homage to the man who opened the door to modern Witchcraft and not just some random boy's name his parents liked, it will still function fabulously as being a very pagan and witchy name.
My daughter is Winter Star. I don't know that it's magical, but it definitely has a hippie/nature element to it. My oldest is Rages, it was a Persian city in Biblical times. I've also heard Apollo Jason (of course he went by A.J.). Goddess and God names are always fun and there's plenty from different backgrounds with different meanings. Morrigan is a popular witch name, maybe too popular. Try babynames.com. You can search by background and meaning. Oh and I've also heard of boys and girls named Pagan or Pagyn.
I was thinking about it and plant or tree names can be magical if you consider the magical correspondences. Daisy, Rosemary, Ash, Sage. I didn't actually look those up, they're just names I know people have. Or maybe a constellation, Cassiopeia or Orion.
Also consider the meaning behind names. My daughter's name means noble victory.
Our names do have a psychology to them and strong names tend to create confidant adults. As your child grows let them know what their name means and/or who they've been named after. It will make them proud of their name.
Stay away from names ending in an "ee" sound as they are psychologically proven to not be taken as seriously when facing peers and in business. For instance, Mary, Lily, Carrie, Danny, and try not to shorten your child's name to such "ee" endings.