I really want to play Pokémon Go but I am a completionist. If I start playing now, what Pokémon won't I be able to catch?
edit: the list is getting a bit out of date. I do not have time right now to update it, but a lot of previous legendaries are obtainable via the 7-day research reward, or coming back into legendary raids. Also, trading is now a thing, making it a lot easier to get everything you missed. The only ones you currently missed are via special quests. These quests should have been picked up (but not completed) in a certain time period. Rewards for those were:
- Meltan (but obtainable via a Mystery Box)
There were multiple limited time Pokemon, mostly legendaries. It is currently not known if they will return (all of them or a select group). These Pokemon were:
- (Shiny) Lugia
- (Shiny) Ho-oh
Currently there is another legendary active, Latios/Latias (and shiny Ho-Oh), so be sure to catch that one while it is still possible. Also Mewtwo is available through Ex-raids at this moment in time.
The legendary birds (Articuno, Moltres, Zapdos) were twice catchable. First a week per bird, then about another month where all 3 birds were available at the same time. Now Zapdos is available by finishing a research quest on 7 individual days. Moltres was already available. Articuno will be available in June.
Another 'issue' might be the special hats for the Pikachu family. At specific moments in time they were catchable/hatchable with a different hat.
One other thing that might be annoying is that there are regional Pokemon. For example, Farfetch'd is limited to Asia only. However, there has been an event where it was catchable for 48 hours worldwide. You can still catch Farfetch'd in Asia, but not so soon in your hometown (if not located in Asia) though.
The regions of Seviper and Zangoose are switched right now. Catch the one that should not be in your location!
Posting an updated answer since the old one is outdated.
Kanto Pokedex. All Pokemon are obtainable.
Jotho Pokedex. All Pokemon are obtainable.
Hoenn Pokedex. All Pokemon are obtainable.
Sinnoh Pokedex. The unobtainable Pokemon are:
- Rotom (all forms except Mow and Wash are unobtainable)
- Phione and Manaphy
- Arceus (all forms)
Unova Pokedex. All Pokemon are obtainable, but some alternate forms are unobtainable:
Zen mode Darmanitan (Unovan and Galarian, base modes are available)
Kyurem-Black and Kyurem-White (base form is available)
Keldeo Resolute form (base form is available)
Meloetta Pirouette form (Aria/base form is available)
Kalos Pokedex. The Pokemon listed below and their evolutions are unavailable:
Alolan Pokedex. All Alolan forms of Kanto Pokemon are available. The Pokemon listed below are unavailable:
Mudbray + Mudscale
Type: Null + Silvally (all forms)
Minior (all forms)
Necrozma (all forms)
Magearna (both forms)
Poipole + Naganadel
Galarian Pokedex. The following Pokemon and their evolutions are available, in addition to all Galarian forms except Corsola:
Zacian (base form only)
Zamazenta (base form only)
Zarude (base/non-Dada form only)
Hisuian Pokedex. The unavailable Pokemon are:
Hisuian forms for Lilligant, Zorua + Zoroark, and Sliggoo + Goodra
White-Stripped Basculin and its evolution Basculegion
Enamorous Therian form (base form available)
Paldea Pokedex. See this list for available Paldean Pokemon. Paldean Wooper is also available.
Unknown Pokedex. All Pokemon are obtainable (Meltan and Melmetal)
Many of the obtainable Pokemon can't currently be caught, for example most legendaries. If starting now, you'll need to trade with a player to obtain these Pokemon. Unfortunately Mythical Pokemon other than Meltan and Melmetal can't be traded. Mythicals that aren't currently available cannot be obtained until they became available again. Fortunately Mew, Celebi, Jirachi, Victini and Shaymin are available through special quests without a time limit. Hence the unobtainable Pokemon that have previously been released are:
- Deoxys (all forms)
- Keldeo (base form, requires purchasing a Something Extraordinary Ticket from 6th to 11th Dec 2022 and completing the Special Research)
- Meloetta (Aria/base form)
- Genesect (all forms)
- Zarude (must have started Special Research quest from 1st to 10th Oct 2021)