I did this for fun recently... and possibly was a bit too generous. But, hey! :)
For those unaware of tier rankings, “S-tier” is the top, followed by A, B, C, D, and finally F.
S-Tier:
Lost Mine of Phandelver (original starter set)
Curse of Strahd
A-Tier:
Hoard of the Dragon Queen
Rise of...