Mass Hellion into Double Armory Thor
From Liquipedia Starcraft 2 Wiki
Using a standard Reactor Hellion Expand (vs. Zerg) but adding a second Factory for more Hellions to pressure the Zerg, with Infernal Pre-Igniter and +1 Vehicle Weapons return to the pre-Patch two shot of workers; and then working quickly to Factory (3) with two Tech Labs on Factory (2) (3) for Thors to counter Mutalisk.
This makes for a strong Mech opening vs. Zerg that continues to man-handle Zergling, Baneling and even Roach openings that make easier Drone murder and make Hellions until Command Center (2) has landed for enough access to Refinery (3) (4) for a strong Mech mid-game. Though Marauders may be needed to stop Roach-Rushes.
Mass produce Hellions off of two Factories to pressure Hatchery-Tech units and make for more opportunities to attack Zerg's mineral lines. Making for a more secure low-ground expansion and time for Thor production to counter Mutalisks, probably into a Siege Tank push but more likely for double Armory upgrades to make for a stronger push timing while having the Hellions to push into the Zerg's base, and make the usual ability to mass large Zergling/Baneling forces null.
 Basic Build Order
- Pressure is scouting.
- Roach Warren? > Marauders + Bunkers
- Spire? > Switch Factory (2) (3) to Tech Labs > Thors
- Use Hellions to pressure Zerg into more Spine Crawlers and switch to Medivac-drop once they finish walling off the natural.
- When the Third mining base shows up, push out with Siege Tanks and take your third base, keeping in mind Hellions need to patrol for Zergling Back-Stabs. And keep the watch towers.
- Or on macro-focused maps, push out out 2-1 Armory upgrades for a stronger push, but the Zerg will have a stronger economy so the push needs to be more methodical.
- Hellion + Banshee Opening. To force even more Queens and Spore Crawlers, using a quicker Siege Tank push with Marines (for speed) to then Siege break the Spore Crawlers and Banshees with cloak are part of a stronger game plan for abusing pre-Lair/Overseer tech.