I like a lot of Alt-rock, but my favorite bands/songs are:
Twenty-One Pilots (Specifically: every song they've ever made),
Thousand Foot Krutch (Specifically: Wish You Well, Untraveled Road, Be somebody, and War of Change),
Anberlin (Specifically: Younglife, Unstable, and Intentions).
Other alternative bands/artists i like include:
Owl City, Starset, Coldplay, Bastille, Hurts, Red, VERIDIA, Of Monsters and Men, Imagine Dragons, Anchor & Braille, FM Static, Sherwood, Yellowcard, and Silverline to name a few.
I know that not all of them fit into the "rock"/"metal" genres.