Here's some wishful thinking of mine:

Legends Class
Quintessons!!! judges, Executioner, scientists?
Spike/Daniel (Exo suit from MP Bumblebee???)

Deluxe Class
G1 Gnaw
Impactor
Rack n' Ruin

Voyager Class
G1 Rotorstorm

Leader Class
Overlord

Titan Class
G1 Omega Supreme