The of Kadokawa has a trailer for an official crossover of KonoSuba, Overlord, Re:Zero & Youjo Senki (Saga of Tanya the Evil). : r/Konosuba

Isekai Museum in Japan features Re Zero Overlord Konosuba The Saga of Tanya the Evil 0015 - Anime Trending

ISEKAI QUARTET KonoSuba Teaser

Konosuba,' 'Overlord' Anime Crossover Releases New Trailer

Youjo Senki (Saga of Tanya the Evil)

I feel like the Overlord community is the only one who appreciates Isekai Quartet : r/overlord

Isekai Museum in Japan features Re Zero Overlord Konosuba The Saga of Tanya the Evil 0007 - Anime Trending

Anime Crossover Youjo Senki Overlord (Anime) KonoSuba – God's Blessing On This Wonderful World!! Tanya Degurechaff Kazu…

ISEKAI QUARTET KonoSuba Teaser

Isekai Quartet, Isekai Quartet Wiki

Isekai Quartet, Isekai Quartet Wiki

Isekai Quartet Movie Shares New Trailer

Konosuba,' 'Overlord' Anime Crossover Reveals New Poster, Release Date

ISEKAI QUARTET KonoSuba Teaser