GuildMaster (Wigglytuff)@Life Orb / Leftovers
Role: Stealth Rock Support
EVs: 252 HP / 252 Sp. Atk / 4 Sp. Def
After experimenting with some sets for Wigglytuff, I found that its niche lies in its Competitive ability and access to Stealth Rocks.
Thunder Wave is good for crippling the opposing sweepers, while Heal Bell provides support for the team.
Stealth Rock is a good entry hazard that can force the opponent to use Defog and, thus, activating Competitive.
Dazzling Gleam + Hyper Voice provides dual STABs. Note that Dazzling Gleam allows Wigglytuff to deal with Fighting-types and Dark-types, such as Poliwrath and Mightyena. Hyper Voice is a good spammable STAB move for dealing with Substitute users and neutral coverage. Focus Blast can be used as an alternative to Hyper Voice, since it deals with Rock or Steel-types that Wigglytuff struggles against.
Maximum Sp. Atk investment + Modest Nature + Life Orb is needed to maximize Wigglytuff's damage output. However, Leftovers can be used to increase Wigglytuff's life span and gives gradual recovery. The full investment in HP is helpful in increasing Wigglytuff's bulk.
Some other options for moves can be a cleric set (in the form of Wish + Heal Bell) but this is generally outclassed by better clerics, such as Lickilicky. Focus Sash is a possible item for reliably setting up Stealth Rocks, but you would have to change the EV spread to 252 Sp. Atk / 252 Speed / 4 Sp. Def
I'll be brief here: Wigglytuff is mainly used for early-game to mid-game and should only set up Stealth Rock when offensive threats are removed (namely Rampardos).
Possible Team Members:
Wigglytuff works well on Balanced or even Bulky Offense teams. For this reason, Poliwrath or Machoke are good options (they also deal with Steel and Rock-types so you don't need to run Focus Blast). Roselia also works well and sets up Spikes and Toxic Spikes. Misdreavus may also provide valuable support in the form of Will-O-Wisp and Taunt and it even acts as a spin-blocker!
Hope I helped!