Ok people, here is the complete list of all 43 Sailor Senshi that I have ever heard of. Most of the ones you'll probably know nothing about are from the manga and Sailorstars drama plays. If you find any mistakes or know more senshi than the ones listed here, please tell me.
1. Sailormoon
2. Sailormercury
3. Sailormars
4. Sailorjupiter
5. Sailorvenus
6. Sailorpluto
7. Sailorneptune
8. Sailoruranus
9. Sailorchibimoon
10. Sailorsaturn
11. Sailorstarfighter
12. Sailorstarhealer
13. Sailorstarmaker
14. Sailorchibichibimoon
15. Sailor Iron Mouse
16. Sailor Lead Crow
17. Sailor Aluminum Siren
18. Sailor Tin Nyanko
19. Sailor Galaxia
20. Sailor Cosmos
21. Sailor Chuu
22. Sailor Coronis (Sailor Kronos in English version)
23. Sailor Mermaid
24. Sailor Mau
25. (Sailor) Phobos
26. (Sailor) Deimos
27. Sailor Kakyuu
28. Sailor Chi (pronounced "kai")
29. Sailor Phi (pronounced "fai")
30. Sailor Heavy Metal Papillon(sometimes "papion" and pronounced "papiyon")
31. Sailor Lethe
32. Sailor Mnemosyne
33. Sailor Ceres
34. Sailor Vesta
35. Sailor Pallas
36. Sailor Juno
37. Sailor Channel(Chanel)
38. Sailor Guccicci(Gucci)
39. Sailor Pewter Fox
40. Sailor Titanium Kerokko
41. Sailor Theta
42. Sailor Buttress
43. Sailor Chaos
-#1 through 14 are written as one word because that's the way it's sometimes written on the Japanese merchandise, so that's how I write it too. I didn't make all of the rest one word because they're either too long or look weird as one word. It's just my opinion that the other names look better as one word, writing them as two words is fine.
-#18, Sailor Tin Nyanko. "nyan" is japanese for the sound a cat makes. So it's like the japanese version of "meow" or "mew". This is how she gets the name Nyanko and wears a cat outfit. "ko" is the ending used in a girl's name, for example: Usa-ko. Some people prefer to call her "Sailor Tin Kitty" or "Sailor Tin Cat" because of this, but that is wrong. If you were gonna give her an english counterpart through translation, it would be something like "Sailor Tin Meow Girl."
-#21 through 24 are senshi that are only TALKED ABOUT in the manga. They never actually appear except for one picture of Sailor Coronis from the back. Sailor Chuu's star seed was taken by Sailor Iron Mouse. Sailor Coronis' star seed was taken by Sailor Lead Crow. Sailor Mermaid's star seed was taken by Sailor Aluminum Siren. Sailor Mau's star seed was taken by Sailor Tin Nyanko.
-#25 & 26 are Rei's crows in their human/sprite form. Phobos and Deimos first appear as Sailors in Supers when Rei gets powered up to Supersailormars and gets Flame Sniper. They are actually never called sailors, but since they wear the sailor collars, I still call them that.
-#27, Sailor Kakyuu, is the princess of the Starlights as a Sailor Senshi. She only becomes a Senshi in the manga.
-#28 & 29, Sailor Chi and Phi are the Sailor Animamates who call themsleves "Star Gardeners." Sailor Phi has an attack called "Galactica Plants Blizzard." Chi and Phi are the 22nd and 23rd letters of the Greek alphabet.
-#30, Sailor Heavy Metal Papillon, is the final Sailor Animamate, but didn't seem to be too strong as she only lasted for 2 pages in the manga before she died. Papillon(papion) is French for butterfly which would explain her butterfly Sailor fuku.
-#31 & 32, Sailor Lethe and Sailor Mnemosyne are the Sailor Animamates of the River of Oblivion and the River of Memory. They are sometimes called the "Desert River Senshi"(which is a name made up by American fans). Sailor Lethe has an attack called "Galactica Musotis Alpastonis" which is a variation of "Myosotis Alpestris."
-#33 through 36 are the Sailor Quartet (aka the Asteroid Senshi by American fans.) They were the Amazoness Quartet under Nehellenia's influence. CereCere became Sailor Ceres. VesVes became Sailor Vesta. PallaPalla became Sailor Pallas. JunJun became Sailor Juno.
-#37 & 38, Sailor Chanel and Sailor Gucci, are not actual Senshi. The names Chanel and Gucci don't even appear in the manga! What actually appears in the manga is "Channel" and "Guccicci." They only appear in one chapter of a section of the manga called Chibiusa's Diary. There are a few sites dedicated to these 2 and they are usually called the Fashion Senshi(for obvious reasons of people thinking that Naoko was trying to actually make a Sailor Chanel and Sailor Gucci). Some people may not consider them true senshi, but I put them up on the list just for theheck of it.
-#39 & 40, Sailor Pewter Fox and Sailor Titanium Kerokko, were only in the live action Sailorstars drama plays back in 1996/1997. They were also Animamates. "Kero kero" is Japanese for the sound a frog makes. It's like the Japanese version of "croak" or "ribbit." So it's the same deal as with Sailor Tin Nyanko. I guess if you call Sailor Tin Nyanko, "Sailor Tin Meow Girl," you can probably call Sailor Titanium Kerokko, "Sailor Titanium Ribbit Girl."
-#41, Sailor Theta, lead Sailor Chi and Sailor Phi in the drama plays. Sailor Theta, Chi, and Phi were originally "shadow insect senshi" in the plays. Sailor Theta was originally Shadow Bee. Sailor Phi was originally Shadow Mantis. Sailor Chi was originall Shadow Bug. The whole Shadow Insect thing never caught on with audiences so they were turned into Sailor Theta, Chi, and Phi.
-#42, Sailor Buttress, is kinda like a shadow version of Sailor Galaxia in the drama plays. She wore a black(instead of gold) armored fuku exactly the same as Galaxia's. The name Buttress may sound weird, but a buttress is an object that supports bulidings. And through the play, Sailor Buttress would follow Galaxia around talking and "supporting" her.
-#43, Sailor Chaos, is just Sailor Galaxia in her "devil" form. This form is seen in the anime(she is never called Sailor Chaos in the anime though), but most people wouldn't consider her a seperate senshi because she is still Galaxia. Well, her armor turned dark and she grew bat wings when Chaos totally overcame her body, which made her look totally different. So, I consider Sailor Chaos seperate from Galaxia.