It depends on what you mean by the anime... like as in just the 30-minute episodes, movies or literally EVERYTHING?
But if you mean everything, then here's them in order sort of
Tamagotchi the movie
Lets go! Tamagotchi! - 12 episodes (but they are about 2-3 minutes long each)
Tamagotchi: Happiest Story in the Universe (another movie)
^Also there are about 3 2-minute long episodes to follow up this (kinda like Lets go! Tamagotchi! which are on Youtube)
Tamagotchi! (the original anime) - 143 episodes
Tamagotchi! Yume Kira Dream - 49 episodes
Tamagotchi! Miracle Friends - 29 episodes
GO-GO Tamagotchi! - 11 episodes (so far, new ones come out every Thursday)
Also, there are english dubbed episodes of Yume Kira Dream (called Tamagotchi Friends webisodes, which you can find on the Tamagotchi Friends website) coming out that are cut down to 5-minute episodes
Most of the original anime and all of Lets go! are on Youtube, including the 25 episodes that are english dubbed, but most of them are in japanese
Yume Kira Dream, Miracle Friends, and GO-GO are on Nosub.tv (where'd you'd have to search たまごっち to find the episodes) But most of the beginning episodes of Yume Kira Dream don't work
I probably forgot some, but that's about all I know of
Hope I helped a bit