By the time a new code comes around this thread will be buried. It's much easier to just let the mods or whoever create a new post whenever a new code is active.
Yep, new codes seem to get posted pretty quickly here.
usually can either be found that way or pinned in the official Discord server.
https://hellhades.com/raid-shadow-legends-promo-codes/
Can always check there, HH team does a good job with it