>>6059032I'd suggest
1. Human Alliance scale: Get Bee, Jazz, Leader class Ironhide with 3P arm cannons, Buster Optimus Prime, Voyager Ratchet.
2. Regular scale (Original Trilogy)): Leader Buster Optimus Prime with 3P trailer, DOTM Voyager Ironide or ROTF Recon Ironhide, Voyager Ratchet or Deluxe Ratchet depending on your preference of scale vs articulation, Deluxe class Jazz (Battle Damaged to get the movie-accurate blaster), ROTF Deluxe Skids and Mudflap, AoE Takara Jolt, Human Alliance Arcee, Chromia and Elita (They're packed with HA Skids and Mudflap, finding them as 2nd hand sells is pretty hard nowadays), DOTM Takara Wheeljack (Hard to come by, rereleased in AoE Takara line as G1 retool and repaint), DOTM Takara Leadfoot(Rare as fuck, you might as well just wait for a rerelease), DOTM Deluxe Roadbuster and Topspin.
For the Decepticons, TF1 Leader Class Megatron, ROTF Leader Class Starscream (with 3P jetpack and saw), TF1/TF3 asia premium Leader Class Brawl, Deluxe Bonecrusher, Leader Class Sentinel Prime.