There are a lot of Pokémon that have wrong data regarding in which games they can be caught, specially before Gen 8. Also version-exclusives are not reflected. Would be nice to fix all Pokémon.
3 total
Related to this, Minior appears twice in the HOME / GO National Dex with forms de-selected. This means the total is 1026 rather than 1025. Please fix this!
Adding onto this, island scan pokemon in SM/USUM are missing, also resulting in certain pokemon only obtainable via breeding (e.g. fennekin in UM) incorrectly marked not available in certain games. I have not yet checked if pokemon obtained from the poke pelago are affected. Furthermore, certain event pokemon are incorrectly marked available/unavailable. Notably Victini is marked as obtainable through normal gameplay in BW, and meloetta missing from SV DLC. I know many more are missing, these are simply a few that caught my attention.
Additionally, a nice feature to implement for the dexwould be indicating pokemon only obtainable in specific games through certain means. This would include pokemon such as babies that aren't found in the wild, or the previous example with fennekin, though the supplemental websites provide this information.
I already mentioned this is discord, but basculin red stripe form is shown as gender locked to male, when it can be either gender. Also, the name lists it as "Basculin - Male" instead of "Basculin - Red Stripe Form"
Another issue i noticed is with Shiftry abilities option, it doesn't list it's gen8 "early bird" ability, which was available in gen8. It was replaced with wind rider in gen9, but it's still available in poke home if deposited from gen8 game.