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 (250 BP)
Fire
V-Create (180 BP)
Water
Hydro Cannon (150 BP)
Water Spout (150 BP at full HP)
Electric
Bolt Strike / Electro Shot (130 BP)
Grass
Chloroblast / Frenzy Plant (150 BP)
Ice
Ice Ball (960 BP on 5th turn after using Defense Curl)
Ice Burn / Freeze Shock (140 BP; strongest Ice move without stat changes)
Fighting
Focus Punch / Meteor Assault (150 BP)
Poison
Belch / Gunk Shot (120 BP)
Ground
Headlong Rush / Precipice Blades (120 BP)
Flying
Sky Attack (140 BP)
Psychic
Stored Power (860 BP with +6 in every stat)
Prismatic Laser (160 BP; strongest Psychic move without stat changes)
Bug
Megahorn (120 BP)
Rock
Rollout (960 BP on 5th turn after using Defense Curl)
Head Smash / Rock Wrecker (150 BP; strongest Rock move without stat changes)
Ghost
Last Respects (5050 BP with 100 teammates fainted)
Shadow Force (120 BP; strongest Ghost move without teammate modifiers)
Dragon
Eternabeam (160 BP)
Dark
Punishment (200 BP after 7 positive stat changes on an opponent)
Hyperspace Fury (100 BP; strongest Dark move without stat changes)
Steel
Gigaton Hammer (160 BP)
Fairy
Light of Ruin (140 BP)
Fleur Cannon (130 BP; strongest obtainable Fairy move)
Shadow
Shadow End (120 BP)
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.
Also, it doesn't include Z-Moves or Max Moves, many of which end up more powerful. This list also ignores OHKO moves and focuses on moves with base power.
