Copy and pasted from CBR.
Zones:
All Zones: Diamond Dust, Astral Shards, Adamantium Fragments, Pym Particles
Asgard: Uru Dust, Dark Energy Motes
Baxter Plaza: Psychic Residue, Unstable Matter
Daily Bugle: Symbiote Drops, Mutagen Solution.
Villainville: Mechanical Bolts, Vishanti Thread
Mayhem Missions:
Dr. Octopus - Mechanical Part, Antimetal, Shadows, Unstable molecules, Dark Energy Motes
Green Goblin - Diamond Dust, Antimetal, Mutagen solution, Mechanical parts.
Venom - Mechanical Part, Mutagen Solution, Antimetal.
Abomination - Mechanical Part, Antimetal, Gamma Spark, Mutagen solution, Psychic Liquid.
Dr. Doom - Cosmic Energy, Unstable Matter, Vishanti wisp, Antimetal.
MODOK - Mutagen Solution, Antimetal, Gamma Spark, Unstable Matter, Psychic Liquid.
Enchantress - Snowflake, Astral Shard, Elemental Sparks, Cosmic energy.
Loki (Avengers) - Snowflake, Cosmic Energy, psychic liquid, Dark Energy Motes.
Loki (Classic) - Snowflake, Uru Coins, Elemental Sparks, Cosmic energy, Antimetal.
Annihilus - Shadows, Cosmic Energy, Mutagen solution, unstable molecules, Antimetal
Mole Man - Diamond Dust, Mutagen Solution, Antimetal
Super Skrull - Psychic Liquid, Elemental Sparks, Shadow, Dark Energy motes, Antimetal, Cosmic Energy
Missions:
A Thousand Apples a day - Elemental Flames, Ice Crystals
Abomination Obliteration - Omnium Ingot, Psychic Solution
All for Jugger-Naught - Omnium Ingot, Negative sparks, Vishanti Thread
Attack Of The Iron - Mechanical Parts, Mechanical Frames, Mutagen Mists
Bombs Away - Omnium Ingot
Breezy Riders - Mechanical Frames
Claw And Disorder - Mechanical Frames
Creatures Of The Night: Negative Sparks, Vishanti Thread, Omnium Ingot
Creatures Of The Night Crisis: Vishanti Thread
Dormammu Mia! - Elemental Flames
Extremis Measures - Omnium Ingot, Negative Spark, Unstable Atoms
Flat broke and rusted - Mecanical Frame
Flame On (And On And On And On) - Omnium Ingot
Freezer Burn: Ice Crystal, Dark Energy Balls, Elemental Flames
Hail to the Kingpin?! - Omnium Ingot, Mechanical Frames, rough diamonds
He's Baack - Cosmic Charge, Dark Energy Balls
Hit the Bullseye (Please) - Negative Sparks
Home invasion: Mechanical frames
Lizard-Ous To Your Health: Mutagen Mist, Omnium ingot
Loki?: Dark Energy Balls, Ice Crystals
Magneteors: Cosmic Charge
MODOK Madness: Gamma Burst
MODOK Madness Crisis: Gamma Burst, Psychic Solution
Modok mo problems - Omnium Ingot
Monster Smash!: Astral Crystals, Dark Energy Balls, Omnium Ingot, Vishanti Thread
Ock It To Me: Unstable Atoms
Onslaught Onslaught - Psychic Solution
Repellant Bugs: Negative Sparks
Seeking Sneaky Mystique: Unstable Atoms
Send In The Clone-Bots Cosmic Energy
Skull and Void! - Cosmic Charge
Strike Of The Spider-Foes! - Mechanical Frames, Mutagen Mist
Super Sized and Magnitized - Omnium Ingot
Symbi-Oh-No - Symbiote Extract, Omnium Ingot
The Gods of Thunder? - Ice Crystals, Elemental Flame, Uru Plates, Uru Ingots
Time To Take A.I.M.!: Astral Crystal, Gamma Burst.
Time To Take A.I.M.! Crisis: Vibranium Ore,
U Turned: Out the Lights Omnium Ingot
Un-Secret Invasion: Omnium Ingot, Cosmic Charge, Elemental Flames
Unstoppa-Skrull : Gamma Burst, Omnium Ingot, Unstable Atoms, Unstable Matter
Very Bad Breath: Omnium Ingot
We Run in Peace: Omnium Ingot
Wen-Di-Go Away!: Vishanti Thread, Omnium Ingot, Psychic Solution
Wen-Di-Go Away! CRISIS: Vishanti Thread
Whack-A-Mole Man: Omnium Ingot, Mechanical Frames
Daily missions: Mutagen mist, Cosmic energy, psychic liquid
Vibranium Ore: From getting Adamantium on Crisis Missions.
Also acquiring the Junkyard Dog sidekick can be of help. If you craft his silver badge, it will cause him to gather parts that are around you with greater ease. While his gold badge will cause him to craft additional parts that can be found in the zone that you are currently in at a rate of 1 per minute.