A list I’ve been sitting on since this began:
Avians:
TSN Condor
TSN Cormorant
TSN Darter
TSN Harrier
TSN Kestrel
TSN Kite
TSN Osprey
TSN Roller
Non-avian animals:
TSN Caiman
TSN Cobra
TSN Hornet
TSN Lynx
TSN Moray
TSN Python
TSN Scorpion
TSN Stingray
Celestial objects:
TSN Arcturus
TSN Castor
TSN Procyon
TSN Pollux
TSN Rigel
TSN Sirius
Constellations:
TSN Andromeda
TSN Aries
TSN Cetus
TSN Cygnus
TSN Fornax
TSN Gemini
TSN Orion
TSN Sagittarius
Virtues:
TSN Diligent
TSN Fierce
TSN Gallant
TSN Relentless
TSN Stalwart
TSN Steadfast
TSN Vigilant
Creatures:
TSN Basilisk
TSN Manticore
TSN Revenant
TSN Siren
TSN Spectre
TSN Wraith
TSN Wyvern
Professions:
TSN Archer
TSN Dragoon
TSN Explorer
TSN Nomad
TSN Paladin
TSN Ranger
TSN Surveyor
TSN Vanguard
Historical figures:
TSN Galileo
TSN Huygens
TSN Kepler
TSN Magellan
Miscellaneous:
TSN Apex
TSN Gale
TSN Hurricane
TSN Monsoon
TSN Predator
TSN Rook
Didn’t care to include any deities.
Restricting the entire fleet to a single theme would, in my opinion, feel a bit cheesy – Captain-Planet-y – and diminish ship individuality. I’d even propose scrapping the palette for insignias (I’d love to do some designs, by the way).