discord-archiver

Archives a Discord server: messages and audit logs.

Uses discord.py and a bot with Administrative permissions to your server.

Usage (bash)

# Set up config.json:
mv config.json{.template,}
nano config.json

# Run it:
python3 archive.py

Threads aren't supported
Role information isn't captured (beyond audit logs, which you could probably use to reconstruct what happened?)

If you want to tweak what this script does, I recommend taking a look at the discord.py API documentation: https://discordpy.readthedocs.io/en/stable/api.html

Should be pretty straightforward to find things which you can add from there.