Both follow a FL who move to the countryside after things that happen in their lives.
Both ML have bookstores and are very smart.

Both consist of kdramas where there is time travel. In Go Back Couple, both couples go back in time whereas in Lovely Runner only the FL goes back in time. They both also consist of leads trying to find love.

ML in Somehow 18 was in love with FL who committed suicide 10 years ago, and finds himself back to before she killed herself. In that time, he strives to stop her from killing herself and to keep her living.

FL has superpowers, similar to The Atypical Family
There is a romance between her and ML
Both include action

Both depict characters with superpowers
Atypical Family depicts only one family who possesses powers

Both short kdramas
Both revolve around the topic of music
Both follow leads who want to follow their dreams

ML are both poor
FL are both from rich families
ML are trying to achieve their dreams
both have to jump through hurdles to stay together