Raichu
Because of the existence of the Light Ball, Raichu can't really match Pikachu in power. Both have bad defenses and HP, so Raichu's somewhat higher defenses sadly don't mean much, considering both are likely to be OHKO'ed. Speed is Raichu's only reedeeming quality, as there are plenty of Pokemon who have a Speed stat between 100 (Raichu) and 90 (Pikachu). In addition, since Pikachu needs its Light Ball, Raichu can hold some other item, like a Focus Sash.
Abilities:
Static: 30% chance to paralyze when physical attack is used against Raichu. It's alright, but Raichu 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 it's also useful to get a free switch in and stat boost in Singles.
Light Ball? Who Needs It?
- Volt Tackle/Wild Charge
- Thunder/Thunderbolt
- Grass Knot/Focus Blast/Reversal/Iron Tail
- Volt Switch
Item: Focus Sash/Life Orb
Ability: Static/Lightningrod
EVs and Nature: Naive (+Spd, -SpDef); 168 Atk/168 SpAtk/172 Spd
Mixed attacking set. Thanks to 5th Gen bringing Wild Charge, we now have a decent physical Electric attack that doesn't cause 1/3 damage recoil. It does 1/4. (I know, not much difference, just mentioning it.) Yeah...maybe stick with Volt Tackle if you don't care too much about that recoil margin. Thunder(bolt) is your powerful special Electric type move. The third move is whatever you want to take out Pokemon immune to Electric type moves. Volt Switch lets you scout.
One Hit Point Wonder
- Flail
- Reversal
- Thunderpunch
- Thunder Wave
Item: Focus Sash
Ability: Static/Lightningrod
EVs and Nature: Adamant (+Atk, -SpAtk) or Jolly (+Spd, -SpAtk); 4 HP/252 Atk/252 Spd
Step 1: Get hit, Focus Sash comes into effect, leaving you with 1 HP. Use Thunder Wave or Thunderpunch if something gets in the way. (Ex: Damaging weather, current foe isn't an attacker, entry hazards, etc.)
Step 2: Use Flail and Reversal to destroy opponents. Thunderpunch to handle Ghost types and against types in which you have supereffectiveness.
Step 3: Keep going until KO'ed.
WARNING: Priority attacks will easily kill you.
Other Options
A few, nothing amzaing.
Charm cuts a foe's attack in half.
Sweet Kiss confuses a foe with a 75% rate. Just leaving confusing to Confuse Rayers would probably be a better idea, though...
Electro Ball can do massive amounts of damage against opponents that are way slower than you. Too situational for me, although it can work.
Agility doubles Speed, although Raichu doesn't have the defenses to give it a chance to set up.
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 Raichu to have. A little bit of free damage at the start isn't too bad, though.
Wish heals whatever is in Raichu's position in the next turn. Could work out well enough, even if Raichu isn't much of a supporter.
Double and Triple Battle Options
Discharge. That's pretty much it. Raichu isn't really suited for these because of its small HP and defenses.
Partners
If you are going to use Raichu in Doubles/Triples, might as well have a Volt Absorb/Ground type partner to combo with Discharge.
Counters
Most Raichu will have a Focus Sash on, so... Entry hazards. Priority moves. If it doesn't have a Focus Sash, any attack that's not resisted by Raichu with decent power behind it will OHKO, especially physical moves.