Yeah, I kinda hated being limited to only level 5 moves when I was still a adventurer, but here is a list of classes that could help.

A Dragonslayer class is a great class, but it takes up a lot of work, you battle a couple of very tough enemies when you actually try to level all the way to 10 or 5.

A dracomancer is also a good class, not the best though, it also takes up some work.

A Shadowslayer and Nighthunter are also both very good classes, great if your on the "Vampire-ish" path.

A Knight is a okay class, but not the best in my eyes.

Those are the classes, let's see if I can there's some good leveling ups

Quest like the Dracopyre legacy are good for level ups

Nightbane is also a very good opponet, he doesn't seem very strong around Lv. 50-70, but he's get's stronger at 80-100, and very strong at 120-150, but he's decent, though.

Battle in the events to, those can ge tyou leveling up also.

Compete in quest like the Devourer saga, those can get you leveling up too.

Compete in the Moglin forest quest (They aren't really worth it since at the start they are like Level 1 monsters, but if you battle them through a very long time, you'll eventually fight some challenging monster's and earn some XP.)