Mute all your discord servers

mute-all-discord-servers.txt

This file helps you mute every discord channel in your account
you have to run it in the developer console on the web client
follow the instructions below. this is tested on firefox and chrome.
                                                
1. open the discord webapp at https://discord.com/channels/@me
2. manually expand all server folders
    (note any servers inside collapsed server folders will not be modified, this can be useful for leaving certain groups of servers unmodified)
3. open browser network inspector
4. right click on a sever icon
5. (un)mute a server
6. find the corresponding PATCH request it went to
     the url should look like https://discord.com/api/v9/users/@me/guilds/954389936121987103/settings
7. copy the contents of paste-into-console.js to clipboard
8. switch to js console, paste this file's contents
9. press enter
10. you should see a popup asking you for a fetch request
10. open the network tab (you can leave the popup open while doing this)
11. locate that patch request in the network tab and "Copy as Fetch"
12. paste that into the alert, press enter
13. watch it go

now all your servers are muted

paste-into-console.js

TIMEOUT_MS = 500;
msg = 'right click a PATCH request to settings, "copy as fetch", paste in here';
my_fetch = window.prompt(msg);
servers = [...document.querySelectorAll(`[data-list-item-id^="guildsnav___"]`)]
  .map((node) => ({
    ch_id: node.getAttribute("data-list-item-id").split("_").slice(-1)[0],
    name: node.getAttribute("aria-label"),
  }))
  .filter((a) => parseInt(a.ch_id));

function ch_id2url(ch_id) {
  return `https://discord.com/api/v9/users/@me/guilds/${ch_id}/settings`;
}

function get_data_from_fetch(fullfetch) {
  lastidx = fullfetch.lastIndexOf("}");
  firstidx = fullfetch.search("{");
  body = fullfetch.slice(firstidx, lastidx + 1);
  j = JSON.parse(body);
  return j;
}

function get_url_from_fetch(fullfetch) {
  url = fullfetch.split('"')[1];
  return url;
}

// basically this completely silences a channel
// it's the equivalent to 
// 1. right clicking a server icon
// 2. checking every box under the Mute Server option
all_checked = {
  message_notifications: 2,
  suppress_everyone: true,
  suppress_roles: true,
  notify_highlights: 1,
  mute_scheduled_events: true,
  mobile_push: true,
  mute_config: {
    end_time: null,
    selected_time_window: -1,
  },
  muted: true,
};


// this is the inverse of above
// effectively "unmutes" a channel
all_unchecked = {
  message_notifications: 0,
  suppress_everyone: false,
  notify_highlights: 2,
  mute_scheduled_events: false,
  suppress_roles: false,
  mobile_push: false,
  muted: false,
};

// this is the object we use to set the desired
// state of our servers
// moodify these objects to get the config you'd like
my_settings = all_checked;

run_new_fetch = async (url, fetchdata) => {
  fetchdata.body = JSON.stringify(my_settings);
  await fetch(url, fetchdata);
  await new Promise((r) => setTimeout(r, TIMEOUT_MS));
};

(async () => {
  for (let { ch_id, name } of servers) {
    let url2 = ch_id2url(ch_id);
    let data2 = get_data_from_fetch(my_fetch);
    await run_new_fetch(url2, data2);
    console.log("done", name, ch_id);
  }
})();

Make sure to click on every folder in your guilds list to expand them, else this will miss those servers and not mute them.
However, it's good if you'd like to whitelist some servers maybe?