A lot of wifi battlers use opener moves such as...
-Toxic Spikes
-Spikes
-Stealth rock
-Leech Seed (Not VERY common!)
...and status dealing moves like:
-Toxic
-Thunder Wave
-Confuse Ray
-Supersonic
-Hypnosis
Some other common moves are self raising or foe lowering moves(TOO MANY TO LIST!)
-Dragon Dance
-Agility
-Trickroom
-Growth
-Nasty Plot
-Acupressure
-Psych up
A LOT of people trick you and slowly sweep using:
-Trick
-Substitute
-Double Team
-Minimize
-Batton Pass
Then finally some normal damaging moves:
-Earthquake
-Flamethrower
-Ice Beam
-Thunderbolt
-Surf
-Brine
-Bullet Punch
-Dark Pulse
-Drain Punch
-Dragon Claw
-Extremespeed
-Leafblade
-Megahorn
ALL OF THESE ARE MOVES THAT I HAVE SEEN IN MY 83 WIFI BATTLES. SORRY THAT I DID MORE THAN TWENTY BUT HOPE I HELPED- ^-^