Leafeon's one of my favorites because its dex says it uses its tail as a sword. I fucking love swordmons. I fucking love swords.
Also I like to think Leafeon can both produce oxygen for underwater dives, retaining the oxygen in a bubble around its trainer, and can steep its tail in warm water to produce tea. This drains the tail of color, but it returns after a while. The kind of tea depends on the season.