Hey Fairy Tail
We all know that Erza is the strongest female FT wizard, some might sat its Mirajane. They were equals when they were younger. I would still lean towards Erza because Mirajane lost much of her to fight after Lisanna died. Even though she got her powers back she doesn't have that killer instinct she had before. After these 2 S-class wizards who would be third. I think it would have to be between Juvia and Cana. They both were elected to the s-class trials and have displayed strong magic power. I know Levy was also elected but I think that was more for her intelligence than magic strength. In fact I would put Lucy right behind Juvia and Cana and before Levy. In the avatar story arc Lucy has gained a considerable amount of power. Even Wendy and Carla have improved. I haven't seen anything new from Juvia but I still bet she can go with the big girls (but only if Gray is threatened or she sees a love rival). Evergreen says shes strong but I really haven't seen her do anything yet. Erza defeated her quite easily in the battle of Fairy Tail. Still I think she is still stronger then most. The rest of the girls I just haven't seem enough of them to even know how strong they are now. Lisanna hasn't used her powers in years while in Edolas but she still seems fairly average. Laki seems to have alot of ability but they haven't shown to many shows with her (I am interested to see what she has been doing after the fall of Fairy Tail). Here is how I ranked them. I didn't rank Porlysica because I don't know the extinct of her power. She seems to be as strong as Mystogan but I don't know if her powers can be offensive. Also Mavis is not on the list because she's dead and we already know she is the strongest. I put Kinana last simple because she doesn't know how to use her powers, if she did i would probably put her above Juvia. She was really tough as a snake.