if you think about it.
depending on which Raikage we are talking, Ay only has a few lightning techniques, while the third raikage alledgedly has the strongest lightning techniques since he can literally tank anything and one shot most things. However if we look at Sasuke he has a lot of different lightning techniques including Kirin and others he has learned from Kakashi. Though if you want to argue over who has the better lightning techniques then you need to ask a question if you simply want to define what the best lightning technique is, because that can be defined by utility, strength or by what types of lightning jutsu that they have, so currently i would say that Darui is considered a very good candidate because he has regular lightning and blacl lightning and wasnt there something about purple lightning or am i wrong on that account. either way another would be the third raikage since he according to manga and anime status could literally tank and fight a tailed beast only using the lightning armor and his finger attacks. so strongest id say third Raikage, Utility would be sasuke due to the abilities capabilities themselves, while for variance i might say darui.