SushiChan
https://sushigirl.tokyo/
It's a laidback weebish imageboard.

Uboachan
https://uboachan.net/
Dedicated to the videogame Yumme Nikki. Kinda dead.

Everfree Forest Channel
https://efchan.net/
Only board is ef, which seems to be a /b/ I can't describe properly.

/cyber/ bunker
nullpo.moe

/a/ bunker
smuglo.li