Colossus Armor - Light - Human

That might have been one of the ones that you could only get through the DLC?

Without Pinnacle Station, some things are probably impossible to acquire now.

I know for a fact that I was able to get Colossus X armor in Light format without Pinnacle Station.  I know it's supposed to appear randomly in stores or in crates after a certain player level.  Colossus Armor is part of the base game, not the DLC in ME1.  Of that I am certain since it randomly dropped/appeared in stores on the original XBox 360 version of the game without Pinnacle Station.  The stores are supposed to refresh their stock after certain missions are completed but I know there's a bug that breaks this in the Legendary Edition since the Spectre Gear disappears if not purchased prior to leaving the Citadel after becoming a Spectre.

The only thing Pinnacle Station did armor-wise was allow the player to gain Colossus X armor much quicker via an exploit using the apartment Shepard could win by beating the Skyllian Blitz simulation on Pinnacle Station...

https://masseffect.fandom.com/wiki/Colossus_Armor

That is a link to the Mass Effect Wiki which shows it coming in Light, Medium, & Heavy formats.  Humans are supposed to have access to all 3 variants depending upon one's Class...  Yet the Light variant hasn't dropped or appeared in stores even once across 3 playthroughs.  I have Savant X Omnitools & Savant X Biotic Amps for all my squad members  that use them (Liara/Kaidan/Wrex/Tali/Garrus).  The only thing missing are Colossus X Light for Kaidan/Liara.

Play Bring down the sky (the dlc) and at the end, the NPC will offer you something, and you can choose any size, weight, or style of Colossus armor. 

I'm replying to myself to add: The Bring Down the Sky dlc is a guaranteed way to get the armor. But I found a second human medium Colossus from one of the vendors on the Citidel. I played this game when it originally launched on the 360 and have never seen Pinnacle station. Sounds like it would have been nice.

You mean Simon the engineer.  EA really needs to fix the Leveled Lists for ME1 & allow Colossus X - Light to drop in random loot lists/crates.  I've gotten every other type of Colossus X to drop randomly/appear in the stores except Colossus X - Light.

I have 2x Colossus X - Heavy - Human (Shepard/Williams), 1x Colossus X Heavy - Krogan (Wrex), 1x Colossus X - Light - Quarian (Tali), & 1x Colossus X - Medium - Turian (Garrus).  I also have the Medium variants of Colossus X for Wrex/Shepard/Williams & the Light variant of Colossus X for Garrus.  The only two I'm missing are the Colossus X - Light - Human for Kaidan/Liara.  Why those haven't dropped in random crates/shown up in stores is beyond me.  All the others were obtained via random crates or purchased from the stores on the Citadel.  These are also supposed to randomly show up in the Requisition Officer's store inventory after one purchases the Kassa Fabrication license from one of the stores on the Citadel or either store on Feros/Noveria.  Like I said, EA needs to fix this...