Untitled

Lower

Boom Your Voice

How to deepen your voice naturally

How to talk with a deeper voice 

How to deepen your voice (pre-t) Voice masculinization

Vocal androgyny in speech and singing

This Phone App Helps Transgender Users Change The Pitch And Tone Of Their Voices (buzzfeed article) 

Higher

Voice Feminization

Pitch, range, resonance, depth

How to develop a female voice

please add links if you got other useful stuff too !

Lower :

Voice Deepening Stretches. a tumblr post with pictures to show how.

How To Deepen Your Voice FTM. Alexander Jasper-Jay on Youtube. Pretty much a tutorial for the stretches from the previous post.

How to Make Your Voice Sound Deeper. Howcast on Youtube. Not FtM related or focused, I think this is mostly for acting ? ? ? 

Higher :

How to make your voice feminine. No head voice. No falsetto. Ada Han on Youtube.

How to Completely Feminize Your Voice. An article by Michela, a trans woman.

Vocal Feminization Guide for any voice type. Impulse Collective DID on Youtube.