SC Arcade went down and the decent combo list with it. X posting here. May generate some traffic. At one point was referenced a few hundred thousand times.

Shout out to Dreamfield. This is largely his hard work put into Boats format that I maintained and modified for 5-10 years as I moderated the Arcade.SC forum.

Rank, Level, and Upgrade amount can exceed stated amount unless specified otherwise. Useful links at the bottom.

Zerg
Swarm Host: 2 L2 Lurker (SS)
Queen: 2 Swarm Hosts + Ravasaur
Brood Lord: Kraith + 2 Queen
3 Drones: 2 L2 Hydralisk (Burrowed) + L2 Roach (Burrowed)
Spore Cannon: 12 Sunken Colony (SSS, Made from Drone)
Vile Roach: 3 L2 Roach + 2 Dark Stalker
Omegalisk: 2 Hybrid Reaver + 3 Kerrigan
Torrasque: Omegalisk (X 90) + 2 Vile Roach
Xelnaga Kerrigan: K5 (300 kills, SXD +300) + Torrasque (300 kills, SXD, +300) + 2 Ravens (X 150)

Terran Bio
Tosh: 2 Spectre + 3 Hammer Security
Tauren Marine: 2 Warmonger (SS)
Murloc Marine: 3 Death Head + 2 Ravasaur (Burrowed)
Toilet: 2 Tauren Marine + Annihilator
Stetmann: Murloc Marine + Toilet
D Marauder: 2 Tauren Marine + 3 Hammer Security
Swann: 2 Dominion Marauder + 5 Automatic Turret (Spawned from Raven)
Tychus: Swann (X) + Stetmann (X)
Covert Ops Nova: (KR Server Only) CRaynor (300 kills, SXD, +300) + Tychus (300 kills, SXD, +300) + 2 Omegalisk (X 150)

Terran Mech
Laser Drill: 3 Siege Breaker + 2 ARES
Nuke Silo: Toilet + 2 Garbage + Crimson Archon
Hercules Bomber: Raven (X) + Science Vessel (X)
Widow Mine: 12 Spider mines (Spawned from Vulture)
Warhound: 2 Spartan Goliath (SS)
Garbage: 2 Dark Zealot + 3 Diamond Back
Raven: 2 Widow Mine + 3 Warhound + Garbage
Arch Fighter: 4 Arch Angel (SSS)
Pirate Capital Ship: 2 Arch Fighter + Hyperion (X, 90)
Terra-Tron: Gorgon (300 kills, SXD, +300) + Pirate Capital Ship (300 kills, SXD, +300) + 2 Swan (XD)

Protoss Bio
Crimson Archon : 4 Dark Archon
Lasarra : Crimson Archon + 3 Stone Zealot
Dark Templar : Dark High Templar (SS) + Dark Zealot (SS)
Centurion : 2 Dark Templar (SSS exactly) (Mix of SS+ for 50/50 Sent/Cent chance)
Blood Hunter : 2 Centurion + 2 Purifier Adept
Alarak : 2 Blood Hunter + Hybrid Dominator (X)
Sentinel : 2 Dark Templar (SS exactly) (Mix of SS+ for 50/50 Sent/Cent chance)
Accendant : 2 Sentinel + 2 Stone Zealot
Karax : 2 Ascendant + Hybrid Dominator (X)
Talandar : Karax (X, 90) + Alarak (X, 90)
Amon: Artanis (300 kills, SXD, +300) + Talandar (300 kills, SXD, +300) + 2 Tal’darim Tempest (XD)

Protoss Mech
Energizer : 2 Dark Sentry (SS)
Annihilator : 4 Dark Immortal
Warp Prism : Energizer + Annihilator
Mothership Core : Warp Prism + Void Ray
Mohandar : Purifier Colossus (X) + 4 Void Ray
Tempest : 2 Havoc + 3 Dark Immortal
Tal’darim Tempest : 2 Tempest + 2 Crimson Archon
Purifier Mothership : 2 Wraithwalker + Mothership Core
Tal’darim Mothership : Purifier Mothership (X, 90) + Tal’darim Tempest (X)
Spear of Adun : Selendis (SXD 300) + Taldarim Mothership (SXD 300) + 2 Karax (X)

Hybridism
Hybrid Nemesis : Brood Lord (X, 90) + 2 Tassadar (X)
Sarah Kerrigan : Nova (X, 90) + K5 Kerrigan (X, 90)
Hybrid Benemoth : Alarak (X, 90) + 2 Warfield (X, 90)

Neutral
Hybridlope: Artosilope (Lvl 7 exactly) + Tastelope (Lvl 7 exactly)




The "Oh shit I killed merge units and forgot how to make this 1 thing" list:
Spoiler : List :
Zerg
Hybrid Reaver = Kerrigan + Zeratul
Stukov = Kerrigan + Raynor
Leviathan = 2 Hybrid Reaver + Stukov
Kraith = Hybrid Reaver + 4 Brutalisks
K5 Kerrigan = Leviathan + Kraith

Terran Bio
Stukov = Raynor + Kerrigan
Hybrid Dominator = Raynor + Zeratul
Nova = 2 Stukov + Hybrid Dominator
Warfield = Stukov + 4 Specter
Craynor = Nova + Warfield

Terran Mech
Odin = 2x Arch Angel
Void Ray = Arch Angel + Colossus
Hyperium = 2 Odin + Void Ray
Science Vessel = Odin + 4 ARIES
Gorgon = Hyperium + Science Vessel

Protoss Bio
Hybrid Dominator = Zeratul + Raynor
Hybrid Reaver = Zeratul + Kerrigan
Vorazun = 2 Hybrid Dominator + Hybrid Reaver
Tassadar = Hybrid Dominator + 4 Purifier Adept
Artanis = Vorazun + Tassadar

Protoss Mech
Wraithwalker = 2 Colossus
Void Ray = Arch Angel + Colossus
Void Seeker = 2 Wraithwalker + Void Ray
Purifier Colossus = Wraithwalker + 4 Instagator
Selendis = Purifier Colossus + Void Seeker

Neutral
Flower = F Yeti + M Yeti
Teistlelope (Blue deer) = M Yeti + M Yeti
Artosilope (Green Deer) = F Yeti + F Yeti


Gems and unlock conditions
Progression Guide
Discord link for the NA/EU community (Some KR players)