The IDM/electronica music scene as a whole is criminally underrated, it's here where some of the most expressive, original and complex modern music is produced.
Trust me, check out the scene and it'll change your life. I mean that sincerely.
It will be painful to list only 5 as there are so many brilliant producers out there, but I will try to limit it for the sake of brevity, here is the five cream of the crop producers:
Aphex Twin: some would say the king of IDM, a brilliant artist and one of the first to create IDM. His sound is rustic and almost industrial, listening to him is unlike anything quite describable with words.
Squarepusher: Endlessly talented, and thoroughly complex, also one of the first to pioneer IDM. He's constantly changing his sound and adapting, no two albums sound exactly the same.
Orbital: these brothers have been producing since the 80's! They have been masters at this since they're first track, Chime.
Plaid: two friends, they arrived relatively new compared to the others in the established cannon, only really hitting the airwaves in the mid 90's, but brilliant artists, listening to their tracks is like audio whisky, that's how smooth it is.
Lauren Bousfield: more breakcore than IDM but even in those scenes she's underrated, she's most famous for making a track that played after some of pewdiepie's videos. Her songs are always quite dense and you almost always hear a new sample every time you listen to any of her tracks.