The following are artists who have worked on characters cards in Transformers TCG, and which cards we know they provided lines or colours for. It is a very incomplete list, as information about who worked on the original Legends mobile game is a bit scarce.
Unless specified, an artist is credited as doing all sides.
Line Artists

Andrew Griffith
Wave 4
Deadlock (bot)
Detritus
Omega Supreme (alts)
Private Highjump
Private Hot Rod
Raider Caliburst (alt)
Raider Needler
Raider Spinister (alt)
Sergeant Crosshairs
Sergeant Soundblaster

Bryan Sevilla
Wave 5
Tidal Wave (all)

Casey W Coller
Wave 4
Full-Tilt

Dan Khanna
Wave 1
Autobot Hound (alt)
Barrage
Chop Shop
Darkmount
Deadlock
Dinobot Sludge (bot)
Dinobot Slug (alt)
Dinobot Snarl (alt)
Dinobot Swoop
Insecticon Skrapnel
Ransack
Wave 2
Starter Bumblebee
Starter Megatron
Starter Starscream
Starter Windblade
Ruckus
Wave 3
Private Camshaft (bot)
Private Downshift
Sergeant Overdrive (bot)
Captain Elita-1
Captain Ironhide (alt)
Captain Wheeljack (bot)
Major Prowl (alt)
Major Shockwave (alt)
Major Soundwave (alt)
Major Ultra Magnus (alt)
Duo-Charge Electrostatic Photon Cannon
Private Flak (alt)
Binary Edgewind Scythe
Private Sideswipe (alt)
Private Trailbreaker (alt)
Raider Detour
Raider Ion Storm
Raider Laserbeak (alt)
Raider Needlnose
Raider Ravage (alt)
Raider Roadhugger
Raider Storm Cloud (bot)
Raider Visper (bot)
Sergeant Chromia (alt)
Sergeant Hound (alt)
Specialist Flamewar
Wave 4
Captain Astrotrain
Mudflap (alt)
Private Greenlight (alt)
Private Vanguard
Raider Apeface (alts)
Raider Blackjack (bot)
Raider Hyperdrive (bot)
Raider Sights
Raider Tailwind
Specialist Sandstorm
Energon Edition
Cliffjumper
Slipstream
Guido Guidi
Wave 1
Optimus Prime Battlefield Legend (bot)
Wave 2
Devastator
Blaster vs Soundwave
Blaster (bot)
Wave 4
Trypticon (bot)

Ken Christiansen
Wave 4
Captain Impactor (alt)
Shadowsteel Iceblade
Private Fixit
Private Sidetrack
Private Smokescreen
Private Sunrunner
Private Turboboard
Sergeant Mirage (alt)
Nightbird
Energon Edition
Bumblebee
Nemesis Prime

Marcelo Matere
Wave 1
Optimus Prime Battlefield Legend (alt)
Optimus Prime Freedom Fighter (bot)
Wave 2
Springer
Blitzwing
Megatron Arrogant Ruler (Bot)
Wave 3
Captain Starscream (alt)
Raider Cindersaur
Raider Flamefeather
Sergeant Cog (alt)
Sergeant Sparkstalker
Blaster vs Soundwave (SDCC edition)
Blaster (alt)
Eject (alt)
Ramhorn (alt)
Steeljaw (alt)
Soundwave (alt)
Buzzsaw (alt)
Frenzy (alt)
Ravage (alt)
Wave 4
General Optimus Prime (alt)
Lockdown
Lord Megatron (alt)
Sergeant Springer (alts)
Energon Edition
Megatron
Optimus Prime

Sara Pitre-Durocher
Wave 4
Raider Chopshop
Raider Kickback
Raider Nightflight
Raider Novastorm
Raider Ratbat (alt)
Raider Rumble (alt)
Sergeant Barricade (alt)
Sergeant Thundercracker (alt)
Wave 5
Arcana
Colour Artists

Alex Tarca
Wave 2
Starter Starscream (bot)
Wave 3
Captain Starscream (alt)
Duo-Charge Electrostatic Photon Cannon
Private Sideswipe (alt)
Sergeant Cog (alt)
Wave 4
Private Hot Rod
Full-Tilt
Raider Apeface (alts)
Raider Sights
Raider Kickback
Private Powertrain (bot)
Energon Edition
Slipstream

Brian Valeza
Wave 1
Six-Gun
Wave 2
Optimus Prime (alt)
Wave 3
Specialist Flamewar
Blaster vs Soundwave SDCC
Blaster (alt)
Eject (alt)
Steeljaw (alt)
Soundwave (alt)
Ravage (alt)

Cara / TheManlyLobster
Wave 4
Raider Blackjack (bot)
Lockdown
Raider Chopshop
Raider Nightflight (bot)

DarlsDraws
Wave 4
Mudflap
Private Seawatch

Harvey Bunda
Wave 2
Offroad (alt)
Wave 3
Private Camshaft (bot)
Major Shockwave (alt)
Raider Detour (bot)
Raider Flamefeather
Private Lionizer (alt)
Sergeant Skrapnel
Wave 4
Private Sidetrack
Jen Santos
Wave 5
Tidal Wave (Aircraft alt)
Kyxarie Peralta
Wave 3
Private Camshaft (alt)
Captain Elita-1 (alt)
Major Prowl (alt)
Wave 4
Lord Megatron (alt)
Private Turboboard (alt)
Wave 5
Tidal Wave (Battleship alt, Combined)
Energon Edition
Nemesis Prime (bot)
Marcus Reyno
Wave 4
Captain Astrotrain (alts)
Sergeant Soundblaster (bot)
Energon Edition
Nemesis Prime (alt)

Oliver Morit
Wave 3
Specialist Ratchet
Wave 4
Octone
Sergeant Soundblaster (alt)
Wave 5
Tidalwave (transport alt)
Sara Pitre-Durocher
Wave 4
Raider Nightflight (alt)

Shibara
Wave 4
Detritus
Shadowsteel Iceblade
Nightbird (alt)
Sergeant Springer (alts)
Raider Novastorm
Sergeant Barricade (alt)
Sergeant Thundercracker (alt)
Captain Jetfire (alt)
MTX-M2 Anti Gravity Cannon
Wave 5
Arcana
Energon Edition
Cliffjumper

Teritori
Wave 4
Private Highjump (bot)
Specialist Sandstorm
Zoner
Wave 4
Raider Ratbat (alt)
Raider Rumble (alt)
MTX-M2A Guided Missile Launcher