Goblin (melee fast tier 1-2 unit with Defend or resistance to piercing or some other damage)
Goblin Shooter (weak armoured shooter with either burst shots or siege mid-range rocket damage)
Goblin Mech (mid-high tier unit which can be used as either melee normal damage with resistance to everything but spells or in its flying mode with siege splash damage and medium armour. Might not be a fast flyer but more of an average speed based one)
Goblin Steamboat (goblin mid-heavy ship which could also be used as a light transport=not more than 4 units to be loaded at a time)
Goblin Steamroller (effective at crushing infantry with medium armour and shooting ranged unarmoured ranged unis)
Goblin Incinerator (I don't know, maybe some high tier unit with splash damage/abilities?)
Goblin Bombardier (goblin hero based on explosives/AoE abilities and stealth; agility, fragile)
Clockwerk Goblin (resource gatherer and builder?)
Day Laborer (same as above)
Goblin Brawler (strength hero based on damage against stronger units)
Goblin Grenadier (long ranged organic siege unit, fragile but somewhat fast moving)
Goblin Medic (healer/buff giver/disease giver; unarmoured "spell caster")
GoblinHovercraft (fast attacking and moving but somewhat fragile ship)
GoblinWarrior (upgrade to the first unit I linked or something?)
GoblinFireworkerbackup (low damage fast attack splash damage unit; somewhat slow moving and fragile to most attack types)
GoblinSapper (I don't know...)
GoblinZeppelin (transport, siege damage or maybe hits more targets at once with piercing damage; light armoured)
GoblinHeavybot (heavy unit or an upgrade to another, something; have to balance not having too many siege or the same role units though)
GoblinSwashbuckler4 (short ranged unit but with higher damage than long ranged units)
Goblin Fuel Pump
Goblin Juggernaut by Sunchips (melee strong unit with possible support role too, warcries etc.)
Goblin Mage (Variation 1) (magician, necromancer, demonologist, summon based)
https://www.hiveworkshop.com/threads/†-revellion-†s-goblin-engineer.135478/#resource-27577 (Militia type form for goblin workers?)
Goblin Rocket Rider (suicidal flying AoE unit)
Goblin Blaster (shredder upgrade/transition form)
Goblin Submarine (Lowpoly version) (water invisible unit; scouting, stealth tactics sabotage)
HeroGoblinGunslinger (agility hero; shooter, DPS, specialized in killing solo units)
GoblinRemoteAirplane1 (drone or something; scouting, damage; a Gyrocopter copy; could be used as a temporary unit from an ability of a building or something)
GoblinBalloonTroupe (flying unit, slow but good AoE and vs buildings; very weak resistance/armour)
Hobgoblin (fast strong unit but with low movement and resistance)
https://www.hiveworkshop.com/threads/ogre-goblin-cannon-squad.286291/#resource-70381 (could be mid-range siege unit)
https://www.hiveworkshop.com/threads/goblin-engineer.135770/#resource-27588 (ranged unit similar to Riflemen; might have an ability for AoE)
https://www.hiveworkshop.com/threads/hero-goblin-prince-guard.227946/#resource-33944 (not sure if goblinly enough; looks more like an orc)
https://www.hiveworkshop.com/threads/heroblademaster.47439/#resource-20165 (agility hero)
https://www.hiveworkshop.com/threads/pyrix-hellfire.222975/#resource-33366 (sorcerer/witch/spell casting hero)
https://www.hiveworkshop.com/threads/clockwerk-giant.184951/#resource-30580 (higher level clockwork unit for a Tinker like ability?)
https://www.hiveworkshop.com/threads/clockworrior-by-rizz_boomer.162529/#resource-29164 (upgrade to clockwork goblin or just a melee unit)
https://www.hiveworkshop.com/threads/wc2-soc-zeppelin.178444/#resource-30172 (air unit, transport, scout)
https://www.hiveworkshop.com/threads/bombcart-by-rizz_boomer.137767/#resource-27661 (maybe could be useful for something)
https://www.hiveworkshop.com/threads/hero-boom-squad.286275/#resource-67560 (fun hero but would need interesting abilities)