The best teammate is a friend that you practice with consistantly!!
Other tips; try to pick a teammate whose hitboxes occupy different areas than your hitboxes. This way opponents need to adapt, and will make mistakes while adapting. For instance, Fox/Pikachu is bad because they both juggle lots and shffl nairs. Both of these characters will have a rough time against a powerful, floaty, confident opponent like Samus or Marth, and therefore your team is easily countered. DK and Pikachu, however, is an excellent team, as DK can handle a strong ground grab and combo/whiff punishing game while Pika can add the pressure. Opponents will find that spamming a particular style will not work against this team; for instance, A Falco/Falco team could not laserspam DK because Pika would be in their face; a dual Marth team could not keep pika at bay because of the Monkey's punishing bairs and throw combos, followed by well timed.
In this sense, I feel that Gannon is the best teammate for Mario. M can handle the projectile and edgeguard game and take over against low damage opponents with his speed and comboing ability, and also his fthrow and bthrow can lead directly into Ganon's shffled fair, bair or stomp for huge damage and KO power. Learn to spot-dodge Gannon's down-B to get a pesky Marth or Peach off your tail. M-Dsmash to G-fair > lone opponents. Issues here might include that neither is particularly good for fighting two opponents because of their low speed, and Gannon's recovery is very stompable/edgeguardable, and Mario will not be able to support him well while he's recovering.
I think a Gannon second is an excellent counter for top opponent picks like Peach, Sheik, and other Gannons. You may have some trouble against space animals.
To counter Marth, I'd select Sheik or Falco for their needles/SHL.
Peach is the best space animal counter! Her downsmash ***** all, and her arials have similar hitboxes to gannon's. Try this one out: M-Fthrow to P-Float-canceled Fair to M-Dsmash to P-Whatever (Dsmash/Fsmash/Dash attack). May be able to grab again or Fsmash FTW.
To counter Docs or Samuses, another Mario/Doc for caping action. Prefer doc for his better fmash against Samuses and for his pills to cancel missiles, but Mario against Doc for better edgeguarding/recovery. Jiggly's also great here to puff punch and bair/fair pressure projectile spammers. My favorite thing ever is to bthrow jiggly at an opponent! Puff projectile and she comes out swingin'!
Against C. Falcon, Jiggly is also good. Making C.F. whiff and outprioritizing him is key. Peach is also good.
SOLAR: I strongly disagree that Mario is not team-ready. 1) Mario has amasing tie-up and damage racking power, with good, quick edgeguarding. 2) Mario can play on a tight stage; he doesn't hog space so team attack won't get him owned. Ban FD. 3) You're right, Mario isn't great support. That's because his teammate is the support! Mario can take the lead against two opponents, using his cape, grabs, quick smashes and fast combos to make a wall between two opponents and your ally; who can snipe/disable. With team attack off, Mario/Samus is disgusting. Mario/Fox is similarly awesome. Team attack on? Fox, Gannon, Falco, Doc, Jiggly (anyone with a good finisher and a good air game) are all great picks. What say you?
