sudo add-apt-repository ppa:paulo-miguel-dias/mesa
Sudo apt update
This is mesa git. the latest you can get.

sudo add-apt-repository ppa:paulo-miguel-dias/pkppa
sudo apt update
This is the latest stable mesa build.

https://launchpad.net/~oibaf/+archive/ubuntu/graphics-drivers
$ sudo add-apt-repository ppa:oibaf/graphics-drivers
$ sudo apt update
They are both the bleeding edge latest drivers if you use paulo-miguel-dias/mesa or oibaf.

paulo-miguel-dias/pkppa is the latest stable drivers (still more up to date than ubuntus defaults but not as bleeding edge).

From what I can tell, they both do basically the same thing. Although, oibaf supports 19.04 while padoka does not.
Padoka seems to be recommended if youre on an LTS release and oibaf is for point releases.