Thank you!
I used 03 different string libraries doubling the main harmony to try to make the sound more massive, they were Symphoni Essencials, Berlim Orchestral and Session Strings Pro 2. For the higher melodies and basses I used a library called Metropolis Ark, it has a very epic sound. I also used the choirs from it, but I don't know if the samples lost quality in the mix or if I overdid the compression!