It's definitely got to be Kingdra/Machamp. Remember, SP decks have lost basically nothing. LuxChomp is the most popular and most winning SP deck of the format. I am running Kingdra/Machamp myself because of how Kingdra' Spray Splashes 1 every turn to your opponent. put 3 of them with 1 LA Kingdra to counter the opponents fire type. I put a 1-3-3-4 Kingdra along with a 1-2-1-2 Machamp. It sounds like hell, but I almost made it into the worlds grinder last year with Kingdra/Machamp (of course Claydol was out then) but I cannot see how anyone would want to run Kingdra without Machamp. If you do, you WILL NEVER win any 16 or 32 K value tournament (including City's, State's, Regional's, National's, or World's). You will have to eventually face a LuxChomp deck and will auto-loss because of the fact that LuxChomp can set up way before Kingdra can and even if you manage to set up, your opponent can level up Garchomp after free retreat and go at it again. As far as Kingdra/Donphan, It's good if you also put in a line of a Pokèmon that can snipe like Garchomp C, but be able to 1-hit KO it also. Because you are using Donphan' and not Machamp, you really are only attempting to counter Luxray GL and not Garchomp C. Not saying that you need to counter ONLY this deck, but it is the only one that Kingdra at all even struggles against; plus, it is the most popular deck as of now.