Alderamin: Pilot, Steamgunner, Piston Brawler, Technician, Sapper. They have a general theme of being focused on equipment, rather than personal stat gain, and have various passives to enhance their equipment rather than themselves.
Velonta: Whaler, Trident Hunter, Ship Captain, Star Seer, Wave Controller. Most of them have some aquatic ability, as well as a wider array of conditional abilities that trigger based off environmental factors or on the size/amount of enemies.
Overall though, you can always expect basic classes like Fighter, Thief, Mage, Cleric, and such to exist in all nations.
Velonta: Whaler, Trident Hunter, Ship Captain, Star Seer, Wave Controller. Most of them have some aquatic ability, as well as a wider array of conditional abilities that trigger based off environmental factors or on the size/amount of enemies.
Overall though, you can always expect basic classes like Fighter, Thief, Mage, Cleric, and such to exist in all nations.