Hi there, unfortunately I don't think it's possible. Best bet if you're trying to rename all of them to the same new name and they don't have any activity in them yet, is to delete the tasks, create new one with your new name and you could set up as a recurring task to automatically create 50 of them or whatever you specify. Or you can create one and then copy them to the same project (copy the 1, then copy the 2, then copy the 3, to build them faster).
If this helped you, please mark correct to help others : )