Are there any Pokédex able to be completed purely single player?

So I wasn’t huge into Pokémon growing up, but over the last few years I’ve become more interested in the games. I enjoy catching various Pokémon and grinding their levels, but there is one thing that always makes me not enjoy the games.

Not being able to complete my Pokédex.

I am a single player kind of gal. I don’t play multiplayer games too often, and I don’t buy online passes because I’ll never use them. But I would love to be able to complete a Pokédex. I understand that a core component of Pokémon is trading, but I just find it frustrating.

So I wondered, are there any games where I can 100% complete a Pokédex without trading, or using online services?