I'm going to base this off of figures that more or less defined the respectove size class and left an impact on both the community and upcoming toylines rather that just fun or good toys.

• Titan class - Siege Omega Supreme. Siege Omega has such a presence and he's got very good playability with effect parts and weaponizers.

• Commander class (or anything else between Leader and Titan) - Siege Jetfire. He's kind of the only figure worth mentioning in this in-between size and he is accurate to both his show and toy forms. He's easily one of the main highlights in one of HasTak's best lines.

• Leader class - HFTD Starscream. This figure is one of, if not the best leader class figures ever made, and it's easily one of the best Starscream toys ever made. The gimmicks did not hinder the figure's transformation or accuracy, and the conversion was still rather simple. It was such a good design that it not only spawned the MPM line (A repaint of it was MPM-01), but its engineering was used in DOTM deluxe Starscream and nearly perfected in the Studio Series voyager. The inevitable MPM 2.0 has very little to improve upon aside of ankle tilt and waist swivel, as this figure more or less wrote the book on how to do a movie Starscream.

• Voyager class - T30 Springer/Botcon Battletrap. This voyager stands out for being a solid attempt at an IDW design and a very good example of a triple changer that doesn't sacrifice in any of the modes. Botcon Battletrap wears the mold arguably better than Springer, in addition to being a unique take on the character, plus he doubles as a CHUG Dropkick. An honorable mention goes to First Edition Optimus Prime (TFP) as the figure was almost as show accurate as it was difficult to find, making it incredibly valuable. It also appears to have influenced the Studio Series Bayverse Optimus mold in terms of transformation, leaving yet another legacy in its wake.

• Deluxe class - PRID Vehicon. They nailed the show accuracy in both modes and even when the jet version was released, it never felt compromised. In a decade of fantastic deluxes, the simplicity of Vehicon's execution makes him stand out above the rest. Good on you, Steve. Honorable mention goes to First Edition Starscream, who is the definitive TFP Starscream and is almost flawless.

• Legends class - TR Seaspray. He's perfect in my eyes, a work of art. I don't have much else to say as I don't collect smaller figures traditionally.

• Battlemaster - I never picked up any, honestly.

• Titan Master - The elephant one was fun. I didn't collect these.

• Micromaster - Siege Laserbeak. He's a very faithful representation of G1 Laserbeak back on Cybertron and reminds me of his masterpiece figure.

• Prime (PotP) - Honestly, I never got any of these.

• Masterpiece (any size class) - MP-10 Optimus Prime. This figure dominated most of the decade with its many redecoes and it continues to be the definitive Optimus for a decent amount of collectors.

• Combiner (any size class) - POTP Battletrap. I feel that Battletrap was one of the decade's best surprises. Nobody knew he was coming, so nobody had any expectations for him. The only main complaint anyone has for him was that he didn't have a weapon, and the positive reception to him caused a proper Flywheels to be made. It also made some people complain upon finding out Flywheels didn't have two individual robot modes.

 

OK, I had time to think about my list, and here it goes:

• Titan class: Trypticon. Great city mode, well integrated with its own toyline (e.g. Sky Shadow); great partner (forgot its name!); great dinosaur and starship mode. More accomplished than Metroplex/Fortress Maximus, and more integrated than Omega Supreme.

• Commander class (or anything else between Leader and Titan): LG-EX God Ginrai, one of my childhood dreams came true.

• Leader class: Thrilling 30 Jetfire, year after year it stands as one of the best TFs I will even own.

• Voyager class: Combiner Wars Cyclonus, great figure for one my favourite Decepticons, great alt mode, and it can combine!

• Deluxe class: Studio Series Dropkick, it stands out like a TF which should not be possible, achieving two satisfying modes with minimal kibble.

• Legends class: Combiner Wars Shockwave, incredibly fun in its simplicity.

• Battlemaster: Smashdown, it looks great in TR Broadside's hands.

• Titan Master: the black Shuffler which came with LG59 Blitzwing. The Guile's theme of TF accessories.

• Micromaster: Air Strike Patrol, I think these two manage to do better what the Air Defense Team tried to do with the Star Saber, and also provide a more interesting combined jet mode than PotP Darkwing and Dreadwind.

• Prime (PotP): Micronus Prime, its gun mode goes well with combiners.

• Masterpiece (any size class): being Italian, I have to go with MP Wheeljack!

• Combiner (any size class): UW Computron, the most fun, varied and stable combiner of the Unite Warriors line. It's absolutely amazing, and it motivated me to go on and get all UW giftsets.

 

• Titan class: TR Trypticon
• Commander class (or anything else between Leader and Titan): Siege Jetfire
• Leader class: SS Blackout
• Voyager class: Siege Starscream
• Deluxe class: Siege Sideswipe
• Legends class: TR Kickback
• Battlemaster: Siege Calibust
• Titan Master: TR Apeface
• Micromaster: Siege Direct-Hit
• Prime (PotP): Solus Prime
  
• Masterpiece (any size class):N/A
• Combiner (any size class): POTP Abominus

 

• Commander class (or anything else between Leader and Titan): Seige Jetfire
• Leader class: Studio Series 08 Blackout other wise it would be Studio Series 44 DOTM Optimus Prime
• Voyager class: Thrilling 30s Springer otherwise Thrilling 30’s Sandstorm
• Deluxe class: Combiner Wars Air Raid
• Legends class:Combiner Wars Powerglide
• Masterpiece (any size class): MPM03 Bumblebee
• Combiner (any size class): Unite Warriors Computron otherwise it would be Combiner Wars/Unite Warriors Superion

 

Thanks to all those who participated, the write-in stage is now closed.

 

Titan - Trypticon
Leader - TR Sixshot
Voyager - Legends Galvatron
Deluxe - TR Triggehappy
Legends - Skrapnel
Battlemasters - misfire
Titan Master - Shuffler
Micro master- Visper
Prime - Metalhawk
MP - Star saber
Combiner - Megatronia

 

Locking this to prevent confusion, if you want it opened after the fact for commentary or something let me know @rikkomba