There were so many new bands coming out in 2013 that there's no way I can have all of their music listed here, but this is a [short] list of my picks for the 2013 debuts you should already have in your music library.
The Ends Beginning EP Palaye Royale (get it now)
Talking Dreams Echosmith (you're not going to stop hearing their name)
In A Perfect World Kodaline (their debut full length is stuffed full of perfection)
Hunter Hunted EP Hunter Hunted (perfection)
Follow My Feet EP The Unlikely Candidates (those vocals and melodies are like a four course meal for your ears)
Mount Karma Dovetail (folksy in the best way with just enough of an alt-rock sound to keep you happy)
You Could Be Happy Sahara Beck (pure vocals and an acoustic guitar)
I Love You The Neighbourhood (every track's perfection and they're so fun to see live; scream "Afraid")
You Belong Here Leagues (the guys are cool, their music's fantastic, and their live performance is a can't miss)
Sunny Days & Starry Nights The Saving Pointe (get the full length because it'll have something you'll love)
It's a short list; I'm positive I missed something great that I was ranting about earlier, but I'll cover it later when I'm not trying to post every 'end of the year' list within five hours.