Above are some Late Roman cavalry, the Schola Scutariorum Clibanariorum, from Gripping Beast’s Late Roman Cataphracts plastic set. These are based on the illustration in Andrey Negin and Raffaele D’Amato’s Osprey book Roman Heavy Cavalry (1). The shield design is based on the versions in the Notitia Dignitatum but as Luke Ueda-Sarson points out on his site, these are not definitely identified with specific units:

http://lukeuedasarson.com/MagisterOfficiorumE.html

Below are Late Roman command figures by Footsore Miniatures and two Late Roman scorpions with crew by Wargames Foundry.