With all of the hits that Shawn Mendes has dished up in just three years, it's almost hard to believe that he's only released two albums (and that he's only 18). Since he released his first single, "Life of the Party," Mendes' songs have captured the hearts of millions around the world, thanks to his smooth voice and acoustic guitar mastery -- and he continued the allure with his latest single, "There's Nothing Holdin' Me Back."

If you dig into all of the Shawn Mendes song catalog, though, you'll see that he's crafted some pretty fantastic tunes aside from the catchy singles. Sure, the ones on the radio are great, but it's the deep cuts that really show Mendes' artistry and vocal ability.

In honor of Mendes' most recent release, Billboard dove into his entire collection and picked out the ones that are the most gush-worthy without being as well-known (at least to those who aren't Shawn superfans). Take a look at Mendes' best deep cuts below.

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"The Weight"

The chorus is the standout in this track, as the fluctuation of Mendes' voice showcases his range. That's not to say that the rest of the song doesn't do his voice justice, though, incorporating plenty of falsetto as well as lower-noted moments while he campaigns for a girl to pick him over another suitor. 

"Ruin"

Mendes has been referred to as a "young John Mayer" and has even cited the "Gravity" singer as one of his biggest inspirations. This Illuminate track may be the best indication of Mayer's influence, featuring almost hypnotizing guitar and perhaps the most soulful vocal display on any of Shawn Mendes' songs yet.

"Strings"

There's a sense of Ed Sheeran in the verses of this Handwritten tune, with Mendes speeding up his singing so much that it almost sounds like he's rapping -- and it totally works. But Mendes doesn't completely jeer away from the acoustic sound and his signature crooning in the song, bringing both back in the chorus. 

"Hold On"

Considering most of Mendes' material was written before he was even a legal adult, the fact that he co-wrote almost every song is already impressive. "Hold On" may be the most personal of them all, using raw lyrics to say that life moves so fast, it can sometimes take a toll on your emotions ("I can't remember being small / I try to figure it out / I can't seem to find out how / I guess I don't know much at all").

"Air" featuring Astrid S

While Mendes' collaboration with Camila Cabello, "I Know What You Did Last Summer," is tough to beat, the only other collab he's done so far puts up a pretty good fight. It's much slower-paced, but that allows his harmonies with Astrid S to shine -- especially on the sharps at the end of the chorus.

"No Promises"

Mendes includes falsetto in many of his songs, and "No Promises" is no exception. In fact, the chorus of the song is almost all upper-register moments. He clearly wanted to highlight that, keeping the verses lower and slower as a build up -- making the higher and bigger notes even more striking. What's funny is that it's the shortest song in his catalog, but all that he does vocally in just two minutes and 46 seconds makes it feel like one of his most dynamic.

"One of Those Nights"

This EP track may be the least Mendes-sounding of this bunch, and maybe that's because it's one of his earliest tracks. Or maybe it's because the topic of the song is more anthemic than Mendes' typical love-based tunes, telling the tale of a night to remember with his buddies.

"Don't Be a Fool"

There's not really a Shawn Mendes song that doesn't have at least a little passion in it, but he presents quite the fervent plea to a girl in "Don't Be a Fool" -- instead of pleading in a lustful way, though, Mendes is actually breaking things off with her. Even so, he does it in the most poetic, heartfelt way possible, all the while doing some of his most striking vocal work to date.

"Imagination"

Easily one of the more swoon-worthy songs of Mendes', "Imagination" doesn't just melt your heart because of the "I want to be with you" story it tells ("In my dreams you're with me / We'll be everything I want us to be") but also because of the way he presents that story with the music.

"Honest"

Every Mendes track includes his acoustic guitar in some capacity, but those chiller vibes are practically most prevalent in "Honest." With lighthearted guitar and soft vocals, "Honest" is perhaps the sweetest way to break someone's heart ("I hate to hurt you but I got to be honest / I can't give you what you need / Oh, you deserve more than I can promise") -- which makes Mendes seem like even more of a stand-up guy than he appears on stage.