So I've just clocked in at 1600 hours as I finished my 17th play through. I've played every race and tried to see as much content as possible. This list is purely based on unique interactions and has nothing to do with combat potential. I've tried to omit as many spoilers as possible. I didn't play every Sub-Race, but I tried to play the sub-races that I thought would have the most dialogue. The only major Sub-Race I didn't play was Wood Elf.

NE COMMENCEZ JAMAIS BALDUR'S GATE 3.
Ce jeu va aspirer votre vie, la macher, la digérer et ne jamais vous la rendre.
C'est trop tard pour moi, mais vous... FUYEZ PAUVRES FOUS !

Sinon, le reste du post détaille les intérêts de chaque race jouable en fonction de ses interactions (romances, options de dialogues, événements...) au fil du jeu.
Purée, 1600 heures...