Oh man this is my thing. Haven't read the rest of the thread, so there may be repeats.
Roman:
Legionary
Centurion
Legatus
Emperor
Praetorian
Plebian
Prefect
Mythology (I mean, you guys did do Skyward Collapse, but still worth listing):
Cerberus
Medusa
Eirene
Phoenix
Minotaur
Charybdis
Scylla
Jormangandur
Ragnarok
Polyphemos
Valkyrie
Ajax
Odysseus
Loki
Odin
Thor
Freja
Eirene
Hyperion
Narcissus
Tantalus
Sisyphus
Prometheus
Menotius
Helen
Achilles
(and so on, there is no shortage of ancient gods, heroes, and creatures from which to draw)
Scientists/Philosophers/Mathmeticians:
Bohr
Mendeleev
Tesla
Curie
Einstein
Bell
Wahl
Compton
Feynman
Turing
Von Neumann
Aristotle
Newton
Plato
Socrates
Archimedes
Pythagoras
Fermat
Battles:
Dunkirk
Blitz
Overlord
Utah
Omaha
Sword
Juno
Gold
Dakar
Calais
Lille
Agincourt
Verdun
Normandy
Hastings
Lexington
Concord
Midway
Thermopylae
Marathon
Salamis
Stalingrad
Leningrad
Astronomy:
Io
Eros
Phobos
Deimos
Kuiper
Europa
Ganymede
Callisto
Singularity
Supernova
Nebula
Horsehead
Galaxy
Other:
Peregrine
Hoplite
Sovereign
Tunguska
Darius
Vermillion
Liberty
Renegade
Maverick
Xenocide
Manu Dei
Arcturus
Halycon
Tungsten
Storm Warden
Sentinel
Hyperion
Catalina
Teuthida
Leviathan
Colossus
Titan
Goliath
Gargantua
Fairchild
Lancaster
Pensive
Cassiopeia
Monarch
Vanguard
Harbinger
Sunset Serenade
Vendetta
Reluctance
Prospect
Sandstream
Century
Vermillion
Raider
Omega
Shield
Talon
Hammer
Razor
Blade
Scythe
Knifepoint
Needlehead
Razorback
Templar
Potate
Lusitania
Avenger
Vengeance
Wrath
Fury
Apex
Alabaster
Lithium
Hurricane
Tempest
Typhoon
Gale
Generation
Fool's Gold
Podos
Blockade
Skywatch
Tyrant
Punisher
Ravager
Arbiter
Judicator
Executor
Immolator
Execution
Dissolution
Evolution
Indigo
Delver
Zenith
Paragon
Peresepolis
Alexandria
Helios
Heliopolis