Which machines can I use to fight with in the Underground Colosseum?

In the Underground Colosseum you can participate in as 9S, you are forced to use machines you've remote controlled in the past to fight in the trials as.

Naturally, I had the Short Stubby (plus a variant or two), as well as versions of the Short, Medium, and Goliath Bipeds and the Small Flier. However, there were many rooms that were empty, presumably due to the fact I didn't hack whatever type of machine lifeform belonged in them.

That said, what machines am I able to fight as in the Underground Colosseum?

After confirming that there are, indeed, 12 rooms for machines to be in, I believe I've found a list of all of the machines that you can control for these arena trials. From here:

• Small Stubby (fists, gun, shield, saw)
• Small Biped (fists, spear, axe, sword)
• Medium Biped (fists, spear, axe, sword (those 4 with shield option), gun)
• Medium Flyer (single, 4 gunners)
• Goliath Biped
• Goliath Biped Legpower Model
• Linked Sphere (saw, gun, drill) The thorn is not used because it's integrated with the drill here.
• Reverse Jointed Goliath
• Medium Quadruped (quadruped, humanoid, mounted)
• Small Sphere (axe, gun, drill)
• Multi-tier Type (Gun equipped only)
• Multi-leg Medium Model (sword, gun = close range, long range)

The multi-tier type standing behind the Medium Biped and the Small and Medium Exploder type machines (as well as the Medium Flyer types that have Exploders on them) are the only controllable machines that are unavailable for the arena trials. (That type of multi-tier machine has no attacks and the Exploder type machines just explode, so they really wouldn't fare too well anyways.)