We literally had a favorite pokemon poll in 2019 before SWSH unironically ruined the series
Full results are here:
https://docs.google.com/spreadsheets/d/17ne51l0NkIqdRPzsV0r50Iut8et8Hc7_GCcSeY30XTk/edit?usp=sharingOut of 821 eligible Pokemon, 200 of them got 0 votes and 156 of them only got 1.
The top 10 is:
Volcarona (63)
Aggron (46)
Gardevoir (42)
Metagross (42)
Flygon (40)
Scizor (39)
Tyranitar (37)
Garchomp (37)
Umbreon (34)
Torterra (33)
Here's how many votes each gen got, and the average votes for each Pokemon of that gen. Gen 3 ended up getting the most votes, but Gen 2 has the best votes to Pokemon ratio.
>Gen 1674 --- 4.46
>Gen 2634 --- 6.34
>Gen 3724 --- 5.36
>Gen 4627 --- 5.85
>Gen 5597 --- 3.83
>Gen 6263 --- 3.65
>Gen 7272 --- 3.10
Additionally, here's the Top 5 for each Gen (except 8):
>Gen 1Raichu
Arcanine
Gengar
Charizard, Ninetales, Vaporeon (Tie)
>Gen 2Scizor
Tyranitar
Umbreon
Heracross
Typhlosion
>Gen 3 Aggron
Gardevoir, Metagross (Tie)
Flygon
Swampert
>Gen 4Garchomp
Torterra
Empoleon
Togekiss
Gliscor
>Gen 5Volcarona
Galvantula
Chandelure
Golurk
Hydreigon
>Gen 6Tyrantrum
Sylveon
Greninja, Aegislash (Tie)
Noivern
>Gen 7Mimikyu
Golisopod
Primarina
Incineroar
Bewear