I named all mine after (comparatively) obscure pieces of music by Gustav Holst.

Light cruiser: USS Hammersmith
Cruiser: USS Beni Mora
Heavy Cruiser: USS Brook Green
Exploration Cruiser: USS Egdon Heath
Assault Cruiser: USS Savitri
MU Star Cruiser: USS Cloud Messenger
MU Assault Cruiser: USS Sita

Still have a few in reserve... after I run out, I'll just switch to a different composer.