Rebel: Thief Who Stole the People Prelude (2017)

Both Male lead has taken a path to help the poor by stealing from rich officials. These are both historical dramas which also centered on their love to their father whom they truly care

The plot is quite similar in some ways although there are more characters in the Rebel that will surely make you laugh especially with the ML character

Both are historical dramas set in the joseon era with fantasy elements (more so in moon sun than rebel). Both have the same vibe of sincere love, fight against corruption. But while The Moon that Embraces the Sun centers around the royals and nobles, rebel is more down to earth with story revolving around the normal folk aspiring to make a change. I love both dramas but feel Rebel has that something special that brings authenticity to it that I have yet to find in any other historical drama (that I've seen).

King is very savage and a revolution took place against him to overthrow the king
Also, in both dramas there was a group of people where helping out poor people