I see wild bolt a lot but I don't know where you get it.
You have to be a Storm Wizard who has completed Marleybone to earn and learn Wild Bolt.
Other than that Storm Wizards can make the spell into treasure cards and will sometimes trade them to their friends, so maybe if you have a Storm friend of high enough level(assuming you are not Storm) then maybe you can ask them nicely to make some for you. And even better; if you do this offer to buy the Keen Eyes cards from the library to give the Storm wizard to make these for you :)
You learn it when you finish Marleybone, but only if you are Storm. If you see it a lot from people who aren't storm, they're using treasure cards. Wild Bolt treasures are very popular.
