Update: 9/26/11
This is a port of the full list of Mosaics I used to maintain on the IDW forums, sorted by character. It's broken up into three sections based on faction, plus a fourth section for the special project releases. It will be kept up-to-date as new Mosaics are released.
If you'd rather look through the Mosaics chronologically, please visit Seibertron's lovely gallery of them.
15 Mosaics
Optimus Prime (G1) - "Appreciation" || "Best First" || "Brother" || "Brotherhood Lost" || "Come Get Some" || "Dark Conclusion" || "The Difference Between You and I" || "Last Spark" || "Leader of the Club" || "McMegatron's" || "Prime Factors - Part One" || "Prime Time" || "The Reason Why" || "The Secret Shame of Optimus Prime" || "The Year is 2004"
11 Mosaics
Sunstreaker (G1) - "Brother's Keeper" || "Contempt" || "Double Team" || "Feeling Yellow" || "First Impression" || "Mine's Bigger Than Yours" || "Size Matters" || "Split Decision" || "Sunstreaker's Day Off" || "Twins" || "Up is Down, Black is White"
9 Mosaics
Kup - "Burning Bridges" || "Dark Times Ahead" || "The Last Day" || "Prime" || "Remembrances" || "Sacrifice" || "The Thing About Rumors" || "Two Is Company" || "War Story"
Prowl (G1) - "Answers" || "Command" || "Double-O" || "Down to Numbers" || "Forgive And Forget" || "The Order to Leave" || "Rank" || "Reckoning" || "The Recruit"
Rodimus Prime (G1) - "Everything Changes" || "History Repeats"/"Deja Vu"/"Till All Are Dead" || "In the Shadow" || "Lingering Questions" || "Nightmares" || "Phantoms" || "Prime"
Springer - "Dead Men's Boots" || "Fearfull" || "The Last Victim" || "The Moment" || "No More Heroes" || "Prime" || "Springer" || "Stowaways" || "War Story"
7 Mosaics
Grimlock (G1) - "Badass" || "Grimlock Badass" || "The Joy of Giving" || "Me Grimlock" || "More Than You Can Chew" || "Retribution" || "The Roar"
Hot Rod - "Blazing" || "Dark Times Ahead" || "First Impression" || "Flesh And Blood" || "Guilty Trip" || "In Retrospect" || "Temptation"
Sideswipe (G1) - "Brother's Keeper" || "Double Team" || "The Fate of the Tank Force - Sideswipe" || "Mine's Bigger Than Yours" || "Split Decision" || "Sunstreaker's Day Off" || "Twins"
Ultra Magnus - "Beyond Great" || "Brotherhood Lost" || "The Fate of the Tank Force - Ultra Magnus" || "Into Character" || "A Pale Reflection" || "Prime" || "The Secret Shame of Optimus Prime"
6 Mosaics
Jazz (G1) - "Appreciation" || "Gimme a Gimmick" || "Sacrifice" || "Silent Dance" || "Small Wonders" || "What a Wonderful World"
Omega Supreme - "Bitter Harvest" || "Determined" || "The Last Sentinel" || "Serpent In Heaven" || "Sentinel No More" || "Supreme Recall"
5 Mosaics
Bumblebee (G1) - "Bee-otch" || "Blackest Night" || "Small Thoughts" || "Small World" || "Youthful Ignorance"
First Aid - "Delusions" || "A Duty to Life" || "The Fate of the Tank Force - First Aid" || "Still Life" || "Triage"
Ironhide (G1) - "Burning Bridges" || "The Order to Leave" || "Serve and Protect" || "Shifting Around" || "Way To Go"
Sentinel Prime (G1) - "The Chosen One" || "Dark Future" || "The Last Moments of Sentinel Prime" || "Passing of an Age" || "Sentinel No More"
4 Mosaics
Blaster - "The Genie Has Left the Bottle" || "Losing the Scent" || "Resonance" || "Where the Spark Is"
Bluestreak - "Forgive And Forget" || "Proper Synonyms" || "The Recruit" || "Speechless"
Cosmos - "Cosmic Happenings" || I Am... || "A Matter of Perspective" || "Where the Spark Is"
Hound - "Gimme a Gimmick" || "Images" || "Rain" || "Small Wonders"
Optimus Primal - "Boss Monkey Business" || "Fearless Leader" || "Prime Factors - Part Two" || "Symmetry"
Optimus Prime (Movie) - "Creation Matrix" || "Cybertronian Rites" || "Father's Day" || "The General"
Perceptor - "Genius" || "My Burden" || "Prime" || "Protest"
Ratchet (G1) - "Appreciation" || "The Oath" || "Sworn to Protect" || "Wonderings"
Rattrap - "Denial" || "Farewell to a Friend" || "Gimme a Gimmick" || "The Trap"
Silverbolt (BW) - "The Darkness Within..." || "Gimme a Gimmick" || "Preparations Are Essential" || "You"
3 Mosaics
Alpha Trion - "Into the Future" || "Twins" || "Voice of Experience"
Arcee (G1) - "The Moment" || "Prime" || "War Story"
Beachcomber - "Endings" || "Outcast" || "Reason"
Brawn - "Deception" || "Pure Brawn" || "Survivor"
Bumblebee (Movie) - "A Day in the Life" || "Father's Day" || "The General"
Cliffjumper - "Cliff Hanging" || "Gentle Persuasion" || "Predator"
Hardhead - "Choices" || "In Retrospect" || "The Sting of Scorponok!"
Hot Shot - "Beauty and the Beast" || "The Fastest" || "The Road Less Travelled"
Outback - "Any Regrets" || "Evil Dead" || "They Were the Dream"
Punch/Counterpunch (G1) - "Ghost in the Machine" || "The War Within" || "Was I Asleep"
Red Alert - "Alerts" || "Overwatch" || "Service"
Rhinox - "As a Last Resort, Kick to Restart" || "Last Rite" || "Stars In Heaven"
Seaspray - "Suppleness" || "Urban Legend" || "Wish"
Sentinel Prime (A) - "Drop Test" || "The Gift of Friendship" || "Multi-Tasking" || "Some Bots Have It"
Sludge - "Friend " || "The Gift of Friendship" || "Simple"
Smokescreen - "Proper Synonyms" || "Smoked Out" || "Tormented Joy"
Tailgate - "Complex Human Terms" || "Delusions" || "Sentient Beings"
Tracks (G1) - "Double-O" || "First Impression" || "Ride in Style"
Wheeljack (G1) - "Anything" || "Jacked" || "What Could Go Wrong This Time?"
2 Mosaics
Arcee (IDW) - "The Shape of Things to Come" || "This Never Ends"
Blades - "Fire With Fire" || "Friends in High Places"
Blurr (G1) - "The Curse" || "Still Life"
Dinobots - "Constructicons" || "Primitive to the Core"
Doublecross - "The Greater Good" || "Micromanagement"
Goldbug - "Different" || "Master Spy"
Grand Slam - "Dark Auspices" || "Evening The Odds"
Guzzle - "Dead Men's Boots" || "Value"
Highbrow - "The High Line" || "The Sting of Scorponok!"
Hubcap - "Art of the Deal" || "The Informant"
Inferno - "Alerts" || "By Inferno's Light"
Ironfist - "Anything" || "Dead Men's Boots"
Ironhide (A) - "Behind the Noise" || "Old Friends, Long Gone"
Jazz (A) - "Multi-Tasking" || "Some Bots Have It"
Jetfire (G1)/Skyfire - "Jet-Fired" || "Vantage Point"
Mirage - "The Great Mirage || "Protest"
Monsterbots - "Discrete Conduct" || "Great Expectations"
Moonracer - "Complex Human Terms" || "Just Like in the Movies"
Optimus Prime (A) - "Seriously" || "Things Past"
Override - "The Fastest" || "The Thrill of Victory"
Prima - "Ancient Times" || "The 1101"
Protectobots - "The Magnificent Five" || "Sworn to Protect"
Pyro - "Dead Men's Boots" || "The True Meaning"
Raindance - "Dark Auspices" || "Evening The Odds"
Repugnus (G1) - "A Cut-Out Job" || "It's a Dirty Job"
Rewind - "Discrete Conduct" || "She's Got the Power"
Roadbuster - "Some Will Never Stop" || "Wish You Were Here"
Searchlight - "Micromanagement" || "Penumbra"
Silverbolt (G1) - "Break Away" || "EDC Protocol 300.29"
Sky Lynx - "EDC Protocol 300.29" || "No Sacrifice, No Victory"
Star Saber - "Fatherhood" || "Supreme Commander"
Sureshot - "Being Sure" || "Last Bot Standing"
Trailbreaker - "Obsolete" || "Steal"
Windcharger - "Faster When it Counts" || "Wavering"
1 Mosaic
Air Hammer - "The Hater"
Air Raid - "Fire With Fire"
Airrazor - "Swoop"
Arcee (A) - "Recognition"
Battle Unicorn - "My Little Transformers"
Blurr (A) - "Chained"
Brainstorm - "The Sting of Scorponok!"
Broadside - "EDC Protocol 300.29"
Bulkhead - "Home is Where the Laser Core is"
Bumblebee (A) - "Impossible"
Carnivac - "Friendly Foe"
Cattilla - "Friendly Foe"
Cheetor - "Cheetor"
Chromedome - "The Sting of Scorponok!"
Chromia - "In for the Fight"
Claw Jaw - "Jabberjaw"
Cog - "Maximum Security"
Computron - "The Question"
Crosscut - "Compromise"
Crosshairs - "Down to Numbers"
Crosswise - "It's Alive"
Depth Charge - "Eternal"
Devcon - "Hunter or Hunted"
Dinobot - "Charge"
Doubledealer - "One of Us"
Downshift - "Shifting Around"
Drift - "The Story of Drift"
Eject - "Losing the Scent"
Erector - "Size Matters"
Flame (G1) - "Cash and Kalis"
Flame (A) - "Trigenesis Imperfecta"
Fortress Maximus - "Maximum Security"
Free Wheeler - "Far From Home"
Gears - "Geared"
God Ginrai - "Strength and Honor"
Grimlock (Movie) - "The General"
Grimlock (SG) - "Shattered Future"
Greatshot - "Friendly Sword"
Hauler - "The Missing Piece"
Holi - "Fatherhood"
Hosehead - "Small Part of the Big Game"
Ironhide (Movie) - "Closure"
Jackpot - "Playing The Odds"
Jetfire (A) - "Drop Test"
Jetstorm (A) - "Drop Test"
Jazz (Movie) - "Unknown Soldier"
Jimmy - "Hope"
Jumpstarters - "Stowaways"
Junkions - "Prime Time"
Landfill - "Dirty and Down"
The Last Autobot - "First and Last Autobot"
Longarm (Movie) - "How I Met the Autobots"
Longtooth - "Long Time Suffering"
Mach Kick - "My Little Transformers"
Minibots - "Teamwork"
Nancy - "Rebirth"
Nightbeat - "A Mystery"
Optimus Prime (RID) - "Wayward Son"
Optimus Prime (Armada) - "Wilderness"
Optimus Prime (SG) - "I Will Be a God"
Orion Pax - "Sterner Stuff"
Pointblank - "Once Was"
Powerglide - "The Girl Who Hates Powerglide"
Primon - "The 1101"
Prowl (A) - "Ninja Vs. Ninja"
Punch (A) - "Interrogation"
Punch (Movie) - "How I Met the Autobots"
Radio AM Robot - "The Farm Report"
Rallnox - "The Meals of Sin"
Ramhorn - "Losing the Scent"
Ratchet (Movie) - "Creation Matrix"
Ratchet (A) - "Recognition"
Red Alert (Armada) - "Wilderness"
Repugnus (A) - "If It's Thursday, It Must Be Gaia"
Retro - "Bitter Memories"
Ricochet - "Public Service Announcement"
Rodimus Prime (A) - "First and Last Command"
Rodimus Prime (SG) - "Shattered Future"
Rollbar - "They Were the Dream"
Rotorstorm - "Dead Men's Boots"
Salt-Man X - "The Farm Report"
Salt-Man Z - "The Farm Report"
Sandstorm - "Tearaway"
Scoop - "Scooped"
Sideswipe (Movie) - "Closure"
Sizzle - "Preserved"
Skids - "Daydream Believers"
Sky High - "A Voice in the Dark"
Slamdance - "The Genie Has Left the Bottle"
Smokescreen (Armada) - "Wilderness"
Snarl (G1) - "Double Edged"
Snarl (BW) - "The Hater"
Snarl (A) - "First Words"
Streetwise - "Discrete Conduct"
The Student - "The Final Lesson"
Sunstreaker (Movie) - "Focused"
Swerve - "Counting Down"
Swoop - "Closure"
Technobots - "Scattered"
Tigatron - "Beauty and Perfection"
Tracks (A) - "F.I.G.J.A.M."
Twin Twist - "Warrior"
Under-3 - "The Meals of Sin"
Wasp - "Old Friends, Long Gone"
Wheelie (G1) - "Chasing The Cards"
Wheelie (SG) - "Darkest Spark"
Wolfang - "Kindred Spirits"
Wreck-Gar - "Liar Liar"
Wreckers - "Fearful"
Emirate Xaaron - "Voice of Experience"
