Like explosion is the strongest normal type
You can see yourself by going to http://pokemondb.net/move/all and choosing a type from the menu, then clicking to sort the column. But I will summarize anyway...
NORMAL - Explosion FIRE - V-Create (or Blast Burn for a move more Pokemon can use) WATER - Hydro Cannon ELECTRIC - Lightning Strike (or, Zap Cannon/Thunder/Volt Tackle for more Pokemon) GRASS - Frenzy Plant ICE - Freeze Shock/Ice burn (or Blizzard for more Pokemon) FIGHTING - Focus Punch POISON - Gunk Shot GROUND - Precipice Blades FLYING - Sky Attack PSYCHIC - Prismatic Laser BUG - Megahorn ROCK - Rock Wrecker/Head Smash GHOST - Shadow Force DRAGON - Roar of Time DARK - Foul Play/Hyperspace Fury STEEL - Doom Desire FAIRY - Light of Ruin Remember these are the most powerful only, not the actual best moves. For example Frenzy Plant stops you from moving the next turn so it's not a good move at all.