Suzumiya Haruhi no Yuuutsu, Denpa Onna to Seishun Otoko Recommendations
Even if Denpa Onna lacks the supernatural element that Haruhi no Yuutsu had, it's still about a normal guy surrounded by a cast of weirdos.
Both lead male characters have a harem of eccentric/unusual girls.
The romance between the male leads and their harem is subdued.
MOE factor present, though Melancholy does not rely solely on this to attract the audience.
ESP, paranormal and supernatural powers involved, with Melancholy having explicit examples.
The existence of Aliens is a theme, but the evidence for their existence is strong in Melancholy.
The male protagonists have to deal with seemingly crazy girls who talk about espers and aliens.
Strange girl with a lot of fantaisies, believe in aliens with a puzzled but interested MC
Denpa Onna to Seishun Otoko and Suzumiya Haruhi no Yuuutsu are slice-of-life series that present us with a school setting. In this setting, our male protagonist befriends various girls, but that is not what makes these titles similar. The similarity comes from the fact that the supernatural is a large element shared by each show.