I don't think it is possible, but I am trying to conplete my Micromaster collection.
These are the ones I am looking for:
Autobots Decepticons Air Patrol Military Patrol Sky High Tracer Eagle Eye Bombshock Blazemaster Race Track Patrol Treadbolt Roller Force Battle Patrol Barricade Big Shot Ground Hog Sidetrack Motorhead Sunrunner Battle Squad Flak Meltdown & HalfTrack Construction Patrol DirectHit & Powerpunch Neutro Fireshot & Vanquish Groundpounder Constructor Squad Crumble Stonecruncher & Excavator Takedown Sledge &Hammer Monster Truck Patrol Grit & Knockout Hydraulic Slow Poke Big Hauler Heavy Tread Hot Rod Patrol Greaser Hubs Astro Squad Phaser & Blastmaster Moonrock & Missile Master Metro Squad Wheelblaze & Roadburner Oiler & Slide Powerrun & Strikedown Overload Roughstuff Retro TerrorTread Surge CementHead Pipeline Greasepit Gusher Airwave Hothouse Skyhopper Ironworks Skystalker Groundshaker Blackout Countdown Spaceshot Full Barrel Overflow
They can be either original G1 Micromasters or the Siege/Earthrise versions, as long as they are consistent in resembling the original toys (the two members of the Air Strike Patrol released were not, as they had Cybertronian jet forms).
I did look around, but 75USD for a 4 set or 100-115 USD for a Micromaster Base is a bit too expensive for me.
Also, if anyone knows of where I can find the Countdown Micromaster that came with Titan Omega Supreme for sale separately, I'd like to know where I can purchase this.