This is very hard for me to answer since I use all the warframes. But if I had to make a list I have to put these.
Ash - My favorite warframe, I like his play style as a Stealth Assassin. I play a lot alone so being a solo assassin feels fits me well.
Saryn - 2nd favorite, she is an absolute monster, been a huge fan since her 2nd rework. Melts everything.
Nyx - Till this day she is my most used warframe. I like her because she manipulates the battlefield but she does feel a bit outdated.
Inaros - A health tank, this guy has carried me through many missions, being able to ju