If you're looking for anime similar to Steins;Gate: Hiyoku Renri + Nyan² Crisis, you might like these titles.
Faris is on her way to a competition in Los Angeles and she's invited Okabe, Mayuri, and the rest of the Future Gadget Laboratory to accompany her. However, the gang quickly realizes their American vacation isn't all it's cracked up to be after they're forced to spend the night at a rickety old motel, and Okabe almost gets arrested at the airport! But not even these events can stop the mad scientist from discussing world lines and Kurisu's strange memories.
Ever since the great war of magic, angels have travelled from Heaven to the Earth to watch over the humans, to make sure they don't make the same mistake again. Lasty Farson (code name "Angel Rabbie") is Heaven's newest candidate for angelhood. Her mission: visit the people of Earth and help with their troubles! Unfortunately for Rabbie, her mission may be more difficult than she expected...
Years after an Earthquake destroyed much of downtown Shibuya, the city is rocked by a series of brutal murders. A man eats his own hand. A woman rips open her own stomach and stuffs a speaker inside. Takuru Miyashiro, a student at Hekiho Academy, is investigating these murders as part of the school's newspaper club. But when he finds a break in the case, it turns out to be closer to him than he ever thought...