1. Dunmer - Most interesting backstory and culture, unique architecture, religion , weapons, armour and lore. The Great Houses are so interesting (My favourite is Telvanni ), longest lifespan, best province in terms of geography. Â Some of them are Dagoth Ur , Sotha Sil , Saint Jiub , Divayth Fyr ,Valen Dreth and and half of Vivec. Also enslaved the beastfolk. If you don't agree play Morrowind and then the Tribunal DLC. You will agree.
2. Dwemer - Technology millenia ahead of their time, only race to create robots, extremely unique aesthetic, very isolationist and most of all their downfall story is amazing (Lorkhan's heart).
3. Altmer - Unique religion, aesthetic and incredibly powerful mages (Psijic Order ), nice house system and good geography. Ancestors of most other Mer races. I am also probably the only TES fan to like the Thalmor and the Aldmeri Dominion . Also tallest race.
4. Ayleid - Unique architecture and religion, Umaril the Unfeathered , Welkynd Stones , Dawn magic, used to rule Cyrodil, enslaved the races of men and built the Imperial City .
5. Bosmer - Nice backstory, extremely unique religion, Y'ffre , Green Pact , The Wild Hunt (Look it up) and only race to use predominantly weapons and armour of bone. Also shortest race.
6. Orsimer - Brilliant backstory, unique religion (Malacath ) and have an outcast feel (no province to themselves).
7. Falmer - Really sad backstory, sort of unique religion and have two different styles of architecture, magic, weapons and armour.
8. Maormer - Unique architecture and best seafaring race, snake magic, water magic, live on Pyandonea and their king is Orgnum .
9. Chimer - Just the Dunmer but white. Extinct. Got turned into the Dunmer by Azura for being too full of themselves.
10. Sinistral Elves - Literally just Altmer but they're all left handed. Extinct, the Redguards killed them all. Used to live on Yokuda.
11. Aldmer - the descendants of Sinstral Elves, Maormer and Altmer. Look just like Altmer. Altmer culture and Aldmer culture is the same. One of them was Topal the Pilot.
All this is my opinion.