We have 8 Eevee Evolutions ("Eeveelutions") so far:
Vaporeon
Jolteon
Flareon
Umbreon
Espeon
Leafeon
Glaceon
Sylveon
and of course the original Eevee itself.
Which of these 9 is your favorite? Rank the 9 in order of likeability.
For new possible Eeveelutions, use: New Eevee Evolutions