How many unique Pokémon formes are there?

Bulbapedia has a list of Pokémon forms. As of this time, it contains:

• Pichu, which can be Spiky-Eared Pichu
• Unown, which have a total of 28 different forms (the 26 letters of the alphabet plus ? and !)
• Castform, which due to its ability Forecast, can turn into Sunny, Rainy, and Snowy forms based on the weather
• Deoxys, which can be in Normal, Attack, Defense, or Speed forms based on game (in Gen III) or based on what meteorite you just inspected (Gens IV, V, VI)
• Burmy and female Wormadam, which can have Plant, Sandy, or Trash cloaks based on what terrain it last battled in (as a Burmy)
• Cherrim, which due to its ability Flower Gift, flips between Overcast and Sunshine forms based on whether the weather is sunny
• Shellos and Gastorodon, which have different appearances depending on whether they come from the West coast or the East coast
• Rotom, which can possess appliances to convert to Heat, Wash, Frost, Fan, or Mow forms
• Giratina, which is in its Origin form inside the Distortion World (or it holds the Griseous Orb) and its Altered form otherwise
• Shaymin, which turns into its Sky form upon contact with the Gracidea item and reverts to its Land form at night or if frozen
• Basculin, which can be Red-Striped or Blue-Striped depending whether the game is Black(2) or White(2) (though rare instances of the other can occur)
• Darmanitan, which flips between Standard and Zen mode based on whether its HP is above or below half
• Deerling and Sawsbuck, which match the season of Spring, Summer, Autumn, and Winter (anything other than Spring has to be transferred in Gen VI, as seasons do not exist there)
• Tornadus, Thundurus, and Landorus, which depending on how they are obtained can be in their Incarnate or Therian form
• Kyruem, which can be fused/unfused to Reshiram or Zekrom with DNA Splicers to form White or Black forms
• Keldeo, which converts between Ordinary and Resolute forms depending on whether it knows Secret Sword
• Meloetta, which temporarily changes from Aria to Pirouette form if it uses Relic Song
• Vivillion, which has 18 different player-location-based forms (Archipelago, Continental, Elegant, Garden, High Plains, Icy Snow, Jungle, Marine, Meadow, Modern, Monsoon, Ocean, Polar, River, Sandstorm, Savanna, Sun, Tundra) and 2 event forms (Poké Ball, Fancy)
• Flabébé, Floette, and Florges, which match the colour of the flower bed they're caught in (Red, Yellow, Orange, Blue, White)
• Furfrou, which can be groomed from Normal to Heart, Star, Diamond, Debutante, Matron, Dandy, La Reine, Kabuki, or Pharaoh trims for 5 days
• Aegislash, which converts between Blade and Shield forms when it uses offensive moves/King's Shield
• Pumpkaboo and Gourgeist, which come in Small, Average, Large, and Super sizes
• Xerneas, which is in Neutral mode for cutscenes and Active mdoe for battle