Both Tong and Bullies are centered around fighting school gangs. In both of them there is a clear hierarchy within the school gangs and when they have defeated one group they have to fight against the ones above them.

Both "Black: I Saw the Devil" and "Through the Darkness" are about criminal profiling. They analyse several cases to better understand the mind of the criminal.
However, "Black" is not a drama, but a TV show.
The methods they work with are also different. In Through the Darkness the profiler analyses the criminals mainly by interviewing them. While in Black they analyse letters from the criminals, past interviews and reenactments of the cases.

Both Dokgo Rewind and Bullies are centered around fighting school gangs and defending the people these gangs oppress. The main cast in both of them consist out of three good guys who are great fighters. They take a bullied student under their wings and defend him against the bullies. Also there is a clear hierarchy among the bullies in both Dokgo Rewind and Bullies. Last there is a little bit of romance in both of them.

Both are supernatural dramas with vampire/vampire-like creatures. The protagonist in both dramas transforms into a monster after a traumatic experience. They both also refuse to turn completely into a monster and stay partly human.

Both dramas are about corruption in the school system and the inequality that this causes between students.
My Strange Hero is much more romance centered than Solomon's Perjury which only has a very minor romance in it, and I mean really minor.

Both are action packed dramas with large scale conspiracy behind the scenes. The main protagonists of both dramas are victims of this conspiracy and are out for revenge. Romance is also an important part of both dramas, although maybe a bit more in Iris than in The K2.