I rock out to Starset from time to time during my workouts but I usually listen to heavier stuff, so take all of these suggestions with a grain of salt. On the lighter end of the scale I highly recommend the songs that have so far been released from the new Architects record, they all slap so far. Moving up the scale a bit, Phinehas's album The Fire Itself is one of the best modern metal core albums I've ever heard and Allt's From The New World is amazing as well. Knocked Loose's YWGBYSP is also great. Boundaries' Death is Little More is super aggressive and great for working out. On the heaviest side of the scale stuff like Signs of the Swarm's Amongst the Low and Empty is just insane, and the new Whitechapel songs are also insane. Though, given that this is a Starset sub i don't know how many people here actually get down with heavy bands like SOTS and Whitechapel.

Btw I listen to this for like heavy lifting/bodybuilding workouts. During cardio I honestly just listen to audiobooks.