This is Homeworld FX-Galaxy, a brilliant mod brought by the 9CCN team.
A list of features, taken from ModDB:
Custom (Animated) Main Menu.
6 fully playable races, each with their own playing styles, unique
units, technologies and abilities. Continue your campaign as the
Hiigaran or Vaygr, reclaim past glory as the Progenitors, orchestrate
the revival of the Kadeshi, join the Taiidan Empire in their quest
for galactic domination or accompany the Turanic Raiders as they
transcend their days of space piracy and become a force in the galaxy
that is to be reckoned with.
Customizable in-game Music Player: The mod will randomly select
ambient and battle tracks from the Homeworld Series & Strike Suit
Zero OSTs and play those during your game. Comes with in-game
repeat, shuffle, random and manual select functions to further
customize it. It can also be disabled easily to use the default
soundtrack for the concerning map.
New units for each of the races. These models have been carefully
build from scratch to reflect the original Homeworld concept art as
close as possible and remain true to the concerning race’s
concept/dominant traits at the same time.
And many, many more! For more info, please check HERE.
Now for some screenshots…(taken from the mod’s page)