My collection has seen a major update today. There are a few more items that're still on their way to me, but here's how it's looking right now;
Virtual Pets
20th Anniversary Tamagotchi Mini (Orange-and-yellow with "Tamagotch" logo)
Tamagotchi Gen 1 (Pink-and-green)
Tamagotchi Connexion V2 (Silver-and-black)
Tamagotchi Connexion V4 (Blue-and-red with flame decoration)
Dinkie Penguin (Red)
Cyber Pet 168 in 1 (Black penguin-style casing)
Chuppi (White with birds'-nest design)
Penguin Watch (Pink)
Virtual PETs (32 in 1) (Blue)
Shuku 20 Shunen Tamagotchi Gen 2 (Blue-and-yellow with "Tamagotchi" hiragana design)
Digimon Gen 1 (Yellow)
Toy Story Virtual Friends Space Explorer
Penpy (Green)
Penguin Time (MGA Penguin clone)
Digi Pets Jia Yuan 168 in 1 (Blue heart casing)
Tamagotchi Original Gen 1 (Purple)
Tamagotchi (Game Boy)
Tamagotchi Meets - Fairy Version (Pink)
Cyber Pet (32 in 1) (The Source Wholesale) (White and yellow)
Pac-Man Tamagotchi (Black Maze)
Tamagotchi Original Gen 1 (Sunset)
20th Anniversary Tamagotchi Mini (Transparent Green)
20th Anniversary Tamagotchi Mini (Purple) (Custom wearable Tamagotchi)
GigaPetsAR 2.0 Unicorn (Transparent blue)
Digimon Original (Transparent purple and yellow)
Doraemontchi
MGA Bear (Clone in house shell)
Tamagotchi Friends (Sapphire Gem)
Giga Pets Microchimp
Giga Pets Compu Kitty
Octo-Pets
Nano Fighters Supreme Sumo (Missing battery-cover)
Plushes
Mametchi
Memetchi
Tarakotchi
Mimitchi
Ringotchi (Gotchi Gear Pet Pouch)
Renamon
Gabumon
Pins
Virtual Pet Enamel Lapel Pin Badge (Hand Over Your Fairy Cakes, Etsy)
Keychains
Tamagotchi Metal Keychain (Paladone)
Other
Tamagotchi Mini Card Holder - Memetchi
Tamagotchi lanyard (Blue with yellow flowers) (From Gotchi Gear Pet Pouch - Ringotchi)