the main element is different, in Times it's communicating with someone in the past while A Day is a repetition of the day but both have that "Change the past, Change the present, but with consequences" thing

both The Call and Times are similar becasue they both use phones to communicate between two different time lines and both go with the "Change the past, Change the present, but with consequences" thing

they could be from the same time period as if they happened at the same time and that make me wish WDH could guest role in RWMR ;)

Both have Kim So Hyun and the "kings" in both are really similar, both are easily manipulated, weak and horrible fathers
TTN was more light and romance focused while RWMR might be more political

the vibes of both dramas are kinda similar, and I might even say it's in the same time period, but don't quote me on that ;D

both River Where the Moon Rises and Mr. Sunshine are similar in their amazing strong warrior female leads that can fight on their own

both Sing Again and Miss Back are similar because they try to give unappreciated singers a 2nd chance

both have the same concept, the main is stuck in the human world until they meet a set number of comforted humans so they could resolve their issues

both seem to be about the same thing, how to prepare for reaching 30. and both are slice of life genres

they both had that "Bear Hug" theme, ie a foreign company tries to acquire multiple companies after ruining their stock business talk stuff

both talk about "extraordinary" creatures, and both deal with nose bleeds/headaches and how they're related to those unknown "enemy" though unlike the waterfall blood in sweet home, circle only had drips

both kinda talk about the work environment from a newbies pov. in both they go through alot of tension and struggles trying to understand the dynamics of a not so perfect and suffocating block that one can't easily fit into