Tool you say? Check out Karnivool, Rishloo, Fair to Midland, Leprous, Haken, VOLA, and Caligula's Horse

Too many people hear Tool and think it's great but never dive any deeper into modern prog. There's a whole genre of that stuff!

Edit: also Porcupine Tree and The Ocean, like others said. If you like heavier stuff, then check out Gojira, Slice The Cake, Rivers of Nihil, The Contortionist, and Meshuggah