Google Apps Script

Description
Google Apps Script is a scripting language based on JavaScript that lets you manipulate Habitica and other G Suite products like Calendar, Docs, Sheets, Slides, and Forms. There's nothing to install — code editor right in your browser, and your scripts run on Google's servers. All scripts can be schedule to give a level of autonomy.

Usage
In order to user this feature, you need to have a gmail account. It is recommend to keep all scripts private as you need to embed your Habitica User Id and API Token in the script.

Auto Accept Quests
by cTheDragons

Run hourly, this script will join a quest automatically if the invite is available in your party. function scheduleJoinQuest { var habId = "#HabiticaUserID#"; var habToken = "#HabiticaAPIToken#"; var paramsTemplate = { "method" : "get", "headers" : { "x-api-user" : habId, "x-api-key" : habToken }   }      var response = UrlFetchApp.fetch("https://habitica.com/api/v3/groups/party", paramsTemplate); var party = JSON.parse(response); if ((party.data.quest.key != undefined) && (party.data.quest.active != true) && (party.data.quest.members[habId] == undefined)){ paramsTemplate = { "method" : "post", "headers" : { "x-api-user" : habId, "x-api-key" : habToken }          }      var params = paramsTemplate; UrlFetchApp.fetch("https://habitica.com/api/v3/groups/party/quests/accept", params) } }
 * Go to script.google.com. If this is your first script, this will automatically create a new Google script for you and open an editor for it. Otherwise, edit an existing project by clicking the pencil icon next to it, or create another.
 * Paste the code snippet below into the editor, replacing the spaces marked #HabiticaUserID# and #HabiticaAPIToken# with Habitica User Id and API Token (Leave the quotes). These can be found under the API tab in your Habitica settings.
 * Under Edit, select Current project's triggers. Then add a trigger that runs scheduleJoinQuest Time-driven on a Hour timer with the parameter of Every hour.
 * Save and you're done!

Schedule To-Dos with Google Calendar
by Snickersnacker

The script will create specific to-dos in your calendar on a specified date. Effectively giving a to-do a "start date". function scheduleToDos { var habId = "#HabiticaUserID#"; var habToken = "#HabiticaAPIToken#"; var now = new Date; var events = CalendarApp.getCalendarsByName("HabiticaReminders")[0].getEventsForDay(now); var paramsTemplate = { "method" : "post", "headers" : { "x-api-user" : habId, "x-api-key" : habToken }   }    for (i = 0; i < events.length; i++) { var params = paramsTemplate; params["payload"] = { "text" : events[i].getTitle, "type" : "todo", "priority" : "1.5" }     UrlFetchApp.fetch("https://habitica.com/api/v3/tasks/user", params) }  }
 * Create a new calendar in your personal Google Calendar name HabiticaReminders.
 * Go to script.google.com. If this is your first script, this will automatically create a new Google script for you and open an editor for it. Otherwise, edit an existing project by clicking the pencil icon next to it, or create another.
 * Paste the code snippet below into the editor, replacing the spaces marked #HabiticaUserID# and #HabiticaAPIToken# with Habitica User Id and API Token. (Leave the quotes). These can be found under the API tab in your Habitica settings.
 * Under Edit, select Current project's triggers. Then add a trigger that runs scheduleToDos Time-driven on a Day timer. I have it run between 3-4am.
 * Save and you're done!

At the daily time, the script will harvest all the events in a Google Calendar called HabiticaReminders scheduled for that day. It will then and add them to Habitica as medium priority to-dos. To schedule a future task, simply select the correct day in Google Calendar and add an event with the to-do text as a title. Make sure you add it to HabiticaReminders and not your default calendar. Suggestion is to hide the calendar the rest of the time, so it doesn't clutter the calendar interface.