Buy old Pokémon games?

Hello all Pokémon and Nintendo fans.

I wanted to buy all of my childhood Pokémon games because of childhood memories and also as a sought-after Pokémon collectible. And all of the 1st Gen. Up to the 5th gene, with the corresponding consoles.

My question now, where can I find all these games in good condition and with original packaging, as well as the GBA, GBC, NDS, NDS Lite and 3DS consoles?

I already have the following games:

-Pokémon SoulSilver without packaging and Pokéwalker
-Pokemon black 2
-Pokemon Y
- Pokémon Alpha Sapphire
-Pokemon moon
-Pokemon Ultra Moon
Pokémon Let's Go Eevee
-Pokemon sword

And I wanted to buy the following games as collectibles (with original packaging?):

-Pokémon yellow and Pokémon blue
-Pokemon crystal
-Pokémon leaf green and flame red
- Pokémon emerald
-Pokemon platinum
-Pokémon SoulSilver with Pokéwalker
-Pokemon black
-Pokemon pinball

Where can I find the consoles and games mentioned above?

So on eBay classified ads there are people who sell the consoles and games. Sometimes also with original packaging. Do you just have to search a bit and / or wait.

There are also buying and selling shops that sell consoles and games. You may also find something there.