These are my first three Tamagotchi from 1997-1998. Thankfully they all survived my childhood, and I still have them today. My very first one was the Yellow P1 (pictured here in a P2 box). I like the yellow shell, but my favorite color is green and I had my first experience with buyers remorse. I somehow convinced my parents to buy me the second one, the Green P1. Both P1s don't work well anymore so I immortalized them in the boxes, and I mainly collect translucent shells when possible now. My dad gifted me the Yellow Angel. The Yellow Angel is is good working order, but since it holds a lot of sentimental value I no longer play this one often, and I purchased a vintage Pink Angel for regular play instead.
Top Row: Japanese P1 / P2 Wave 1 / P2 Wave 2
Middle Row: English P1
Bottom Row: English P2
Top Row: English Angel Original / Angel Rerelease
Middle Row: Japanese Umino / Morino / Devil / Santa
Bottom Row: Japanese Licensed Genjintch / Mothra / TamaOtch
Top Row: Japanese Good Luck Chibi / English Mini
Middle and Bottom Rows: English Mini Rerelease
Top Row: English Rerelease P1
Bottom Row: English Rerelease P2
Top Row: Japanese Orange Mesutchi / Green Osutchi
Bottom Row: Japanese Clear Mesutchi / Black Osutchi
The P1 is my favorite Tamagotchi. I do not like the P1 or P2 rereleases. The package claims it is the same, but there are differences and I prefer the original. Genjintch is another one of my favorite Tamagotchi as well.
I don't have a guide for the originals, but other people do.