Ozanari Dungeon is what I’d call a typical fantasy adventure series. This was released in 1989 which is more than 30 years ago although I must point out that it ran from 1989 to 1996.
Typically, in a fantasy adventure, there is always one thing: The MC has hidden powers of some sort.
… Ozanari Dungeon 
Kaji Ryuusuke no Gi is one of a kind. You are unlikely to see anything even remotely similar in the future because such an era has now passed.
Released in 1992, this was released when the manga industry was truly wild west.
This manga takes on politics from inside rather than outside. This itself is very rare as most manga view politics from outsider’s view which is almost always seen as corrupt and, thus, bad.
… Kaji Ryuusuke no Gi 
Break-Age was mentioned in my Yureka review. Therefore, I’ve decided to cover it.
… Break-Age