Fakemon

Fakemon (Fake Pokémon) is the name given to unofficial Pokémon.

Fake Evolutions/Pre-Evolutions
Fake Evolutions are Fakemon who are related with official Pokémon through Evolution. The most popular Pokémon used for this is Eevee. This is mostly done with Pokémon with one or two stages, but fourth stages do exist. Fake Pre-Evolutions are Fakemon that evolve into official Pokémon. These are often called "Baby Pokémon". They are mostly the result of breeding, sometimes with the parents holding an special item. They can also combine two families of Pokémon together, much like Tyrogue combining Hitmonlee and Hitmonchan their families.

Hybrids/Splices
Hybrids are Fakemon created by combining two Pokémon, mostly through breeding. The most notable group doing this is Fuse-Corp from Deviantart. Splices are mostly Pokémon created with official sprites. This is mostly done on Youtube, since it technically is against the rules on Deviantart.

Normal Fakemon
Some Fakemon are not related to official Pokémon. They are mostly Starters and Legendaries.