Only Cotonnee (black) and Petilil (White) can be evolved using the sun stone in Black and White. However, you can catch Gloom and Sunkern after obtaining the national pokedex, or you can simply relocate from previous generations.
Pansage will evolve by using a Leaf Stone into Simisage.
Petilil will evolve with a sun stone, pansage with a leaf stone, panpour with a water stone, and pansear will evolve with a fire stone.
Happiny
It needs a Moon Stone to evolve.
Pansage
Minccino
Moon Stone!
makes electric type Pokemon evolve
Cottonee evolves by sun stone. If you have a sun stone you can evolve it at any time.
You need a Shiny Stone to evolve into Cinccino.
The only Unova Pokemon that evolves with a Leaf Stone is Pansage.
Minccino evolves with the Shiny Stone!