Pikachu
The only reason Pikachu is even considered for competitive gameplay is because of the Light Ball, which doubles its Attack and Special Attack, giving it higher than Raichu's. Yeah, that's great, but it also means that it can't really hold any other item or else it just becomes a worse version of Raichu. The lack of Focus Sash makes Pikachu extremely easily to KO.
NOTE: I know, this is mostly a copy of my earlier post on Raichu, with a few changes to fit with Pikachu.
Abilities:
Static: 30% chance to paralyze when physical attack is used against Pikachu. It's alright, but Pikachu doesn't last long, which hampers its effectiveness.
Lightningrod: Draws in Electric type moves for no damage and increases Special Attack by 1 stage. Mostly for Doubles to help a partner that's weak to Electric, but Pikachu is way too feeble for Doubles. In Singles, it's useful to get a free switch in and stat boost.
In Brightest Day, In Blackest Night, No Water Types Shall Escape My Sight. Let Those Who Worship Ground Types' Might, Beware My Power, Yellow Rodent's Light!
- Volt Tackle
- Thunder/Thunderbolt
- Grass Knot/Iron Tail
- Volt Switch
Item: Light Ball
Ability: Static/Lightningrod
EVs and Nature: Naive (+Spd, -SpDef); 168 Atk/168 SpAtk/172 Spd
Recently rewatched that Green Lantern movie, made a connection with Pikachu's Light Ball. Anyways... This is pretty similar to my Raichu mixed attacker set. Volt Tackle deals heavy physical damage, Thunder(bolt) deals great special damage, the third move deals with Ground types, and Volt Switch lets Pikcahu scout and/or get out of sticky situations. It's one of the very few (or perhaps the only) set Pikachu can use, considering it dies to quickly to use support moves or anything else other than a mixed offensive.
Other Options
Not much, even less than Raichu's.
Electro Ball can do massive amounts of damage against opponents that are way slower than you. Too situational for me, although it can work.
Discharge damages everything else on the field in Doubles.
Encore locks the foe onto the last move they used. Good to use if you have the chance.
Fake Out is a strange move for Pikachu to have. A little bit of free damage and breaking Focus Sash and Sturdy isn't too bad, though.
Double and Triple Battle Options
Don't even consider it. It doesn't matter that Pikachu has Discahrge and Lightningrod, its defenses can't handle...well, anything really.
Partners
If you insist on being completely insane, then use a Volt Absorb/Ground type so you can fire off those Discharges without worry. Also, a Pokemon that's weak to Electric type moves would thank Pikachu for its Lightningrod.
Counters
With its inability to hold a Focus Sash, any attacker that moves faster than Pikachu will kill it.
I'm starting a Nuzlocke in Platinum where I will attempt to make all the nicknames I give Japanese words (Ex: Chimchar = Kaen [Blaze]). I will be starting sometime...this month...maybe next month? I dunno, I'm a really lazy guy sometimes. The comic I make based on it may never come to exist or be created very long after I finish the Nuzlocke, depending on my laziness.