Isekai Quartet

is a Japanese anime series that serves as a chibi-style crossover between Kadokawa's isekai-genre light novels. The first season series aired on April 9, 2019, and a second season was confirmed to air in 2020.

Plot
One day, a magic button suddenly appears. The protagonists in KonoSuba, Overlord, Re:Zero − Starting Life in Another World, and The Saga of Tanya the Evil all press the button and move to a parallel world — another brand new isekai — at where a new story featuring high school life begins.

2nd Season
The chibi-misadventure continues with new characters from The Rising of the Shield Hero and a brief appearance of the main characters from The Hero is Overpowered but Overly Cautious.