Nothing beats a well structured action-adrenaline webtoon! Here are some lists

1. Tower of God
Everything you know is wrong in ToG. Your morals, your
predictions, your hopes and fears will get tossed around in this
violent tsunami of an emotional ride. It's unofficially a masterpiece,
but only because we're waiting to see how it ends. If you're going
to read just one webtoon, read this now.
Read it for free!

2. The Gamer
You've been bored and thought "man, I wish life was more like a
game." This webtoon weaves a world out of this one wish and
mixes magic, the abyss, and good old fashioned gamer grinding
skills to level up. A must read for anyone who games.
Read it for free!

3. unTouchable
For the lovers of understated humor and the romancers,
unTouchable will tickle you with one vampires struggle to make
sense of her feelings for "chicken." Yes, guys will love it. Yes, they
have drama. Yes, it is a delight on every page. You will see beauty
in small things (like a goldfish) and start to realize everything you
have to be thankful for.
Read it for free!

4. The Pale Horse
Simply put, this is one of the most gorgeous webtoons. The style,
color choice, and hidden symbols make this a work of art on it's
own. But it is more than just art, the story challenges good vs evil
similar to how Tokyo Ghoul did but spread the story further over
a lifetime.

5. Tale of Eun Aran
You might read or watch a shounen and think "Yeah, it'd be great
to be a hero and be powerful." But being a hero means that you're
fighting and sometimes the war isn't even your own. This
webtoon is also like a litmus test, do you think they should give in
to the darkness or fight to protect even though it's harder?