Sliders

The sliders (異世界人, isekaijin, people from other worlds) in the Haruhi Suzumiya franchise are, supposedly, humans who jump through different dimensions. Haruhi has sometimes mentioned them along with other supernatural beings. So far none have appeared in the series.

Trivia

 * Kyon is NOT considered a slider during the events of The Disappearance of Haruhi Suzumiya since technically Kyon did not jump to another world/dimension, but was the only one in the world that was not affected as a result of Nagato's tampering by hijacking Haruhi's powers.