>>1823072272 includes Diancie, Hoopa, and Volcanion.
Of the currently-available Gen6 Pokémon, there are only 69.
>>18230647Unlike evolution, but like some or all form changes, Mega Evolutions:
Share Pokédex number
Don't have Pokédex descriptions
Share names
Share move learnsets
Can't be collected in the PC
Will revert to the previous form
Have important changes mid-battle
Can't be obtained, even through trade, until reaching a certain point in the story
Can't be used independently of each other in teams (1 mega per team)
Have, arguably, more design similarity to their originals than most normal evolutions
There's nothing which mega evolution does that's similar to evolution but different from the existing other types of form changes.
If you want to count forms as unique Pokémon too, where do you draw the line? Does Rotom count? Do all the legendary forms (Deoxys, Shaymin, Giratina, etc) count? Cherrim-Sun? Sawsbuck? Vivillon? All 28 Unown? All 4294967296 Spinda? Gender differences? Shinies?