Maybe I'm just missing it too, but it appears to be gone.
Here is a partial list of what the Suicide Resource Compilation contained for anyone who is looking:
Scams Megathread: https://sanctioned-suicide.net/threads/scams-megathread.25509/
Butanediol Megathread: Missing on my end
Decapitation Megathread: https://sanctioned-suicide.net/threads/decapitation.10747/
Carbon Monoxide Megathread: https://sanctioned-suicide.net/threads/carbon-monoxide-megathread.2053/
Exit Bag and Inert Gas Megathread: https://sanctioned-suicide.net/threads/exit-bag-and-inert-gas-megathread.8393
Firearms Megathread: https://sanctioned-suicide.net/threads/guns-firearms-megathread.9042/
Hanging Megathread: https://sanctioned-suicide.net/threads/how-to-hang-yourself.1183
Night-Night Megathread: https://sanctioned-suicide.net/threads/the-night-night-method.6834/
Sodium Azide Megathread: https://sanctioned-suicide.net/threads/sodium-azide-megathread.7465
Sodium Nitrite Megathread: https://sanctioned-suicide.net/threads/sn-megathread.1156
Stan's Guide to SN: https://sanctioned-suicide.net/threads/stans-guide-to-sn.27535/
Forum Terminology: https://sanctioned-suicide.net/threads/acronyms-on-here-for-new-users.6031
Resource - Manipulation Tactics: https://sanctioned-suicide.net/threads/manipulation-tactics.31123/
First Aid Guide: https://sanctioned-suicide.net/threads/first-aid-guide.73
ASH Suicide Wiki:
https://archive.is/R4jm7
SS Suicide Wiki:
https://web.archive.org/web/20211120101251/https://suicide.wiki/w/Main_Page
There was some more in the resource compilation. But this was the main stuff that I saved the links for.