Mochi
I'm sure it's been brought up already, but I think it would be useful for a lot of users to have a way to customise which Pokémon appear in the Pokédex. For example, a toggle for purely cosmetic form changes, like female Butterfree, which is exactly the same as male Butterfree apart from looks, but not female Indeedee, which has different stats and a different learnset than male Indeedee. Of course, a toggle for ALL form changes would be great too, for people who just want to complete the Pokédex in-game for the Shiny Charm and nothing else.
Additionally, it seems the Pokédex (at least for Sword and Shield) contains Pokémon forms that are unobtainable out-of-battle or in Pokémon HOME — at least to my knowledge.
The ones I've seen so far are:
  • Cherrim's Sunshine form
  • Wishiwashi's School form
  • Mimikyu's Busted form
  • Cramorant's Gulping and Gorging forms
  • Aegislash's Blade form
  • Morpeko's Hangry form
  • Darmanitan and Galarian Darmanitan's Zen Mode forms
  • Eiscue's Noice Face form
  • All of Silvally's (and likely Arceus') different types
  • Zacian and Zamazenta's Crowned forms
  • Eternatus' Eternamax form
Once again, I may be wrong on a few of these, I wouldn't know where to look to double-check whether or not these are obtainable through other methods like Pokémon GO, but I'm confident that a handful of these, at the very least, are unobtainable and shouldn't be present in any Pokédex.
Other than that, I also wanted to say the website looks really nice, and has a lot of potential. Keep up the good work!