The full list of subclasses
 Barbarian: Ancestral Guardian,  Zealot,  Storm Herald
 Bard: College of Glamour,  College of Whispers,  College of Swords
 Cleric: Forge,  Grave
 Druid: Circle of Dreams,  Circle of Shepherds
 Fighter: Cavalier,  Arcane Archer,  Samurai
 Monk: Kensai,  Drunken Master,  Sun Soul
 Paladin: Conquest, Redemption
 Ranger: Horizon Walker,  Monster Slayer,  Gloom Stalker
 Rogue: Inquisitive, Scout,  Mastermind,  Swashbuckler
 Sorceror: Divine Soul,  Shadow Magic,  Storm Sorcery
 Warlock: The Celestial,  The Hexblade
 Wizard: Warmage
 A pretty diverse selection but they can be organized by themes. 
 Religious: Forge, Grave,  Conquest,  Redemption,  Divine Soul,  Zealot, kind of The Celestial.
 Feywild: College of Glamour, Circle of Dreams, Circle of Shepherds.
 Shadowfell: College of Whispers, Shadow Magic, Gloom Stalker, Grave, Hexblade
 Defender: Cavalier, Ancestral Guardian
  
 Horizon Walker could fit in with any planar theme, but because ranger can take fey summoning spells fits with the feywild best.