Heyuri

Wapchan: A simple imageboard where anyone can post text and images, mainly focused around retro (pre 2000s) content.
Nihongoch: 外国人と日本語で交流できる掲示板
Ayashii.net: a easy to remember domain for heyuris "/sw/" board
kuz.lol: Kuz's blog
HHS: Heyuri Historical Society
FutabaChannelNeocities: fan made English-language front-page translation project for futaba channel, aka 2chan
BBSDirectory: A japanese BBS directory/navigator
Vidlii: Vidlii! A video sharing website with some people at Heyuri
world2ch: World2ch comeback, being ran by a Heyuri user
Wirechan: A Lain focused community that encourages philosophical, esoteric, alternative, counterculture related, technological and cyberpunk discussion, this being with a mature userbase.

Note: Not all of these are necessarily run by Heyuri, friendly/fan sites are included here as well!