Somewhat similar to Slack, but a custom implementation to send to Discord: https://discordapp.com/
Note that this is achievable right now, using the Slack connector, and Discord's Slack-compatible webhooks.
Simply generate a webhook URL for a Discord channel per the documentation, and add /slack on the end. Then setup the Slack connector as you usually would.

To this end, does Sonarr need a Discord-specific connector? What additional functionality would it provide?
I am on the fence about a discord specific connector. I dont think any discord specific features would be enabled or gained by it, but it also prevents people getting confused about having ot add /slack to the end of Discord webhooks when using the "custom webhook" integration.
However, it also seems that the ability to set an icon to an image URL is about 50% working 50% broken. Any idea why always appears as the default discord logo, 99% of the time?
Posts: https://puu.sh/vYAWe/3562c7da97.png
Settings: https://puu.sh/vYASc/fca1deba9a.png
Thanks @FireEater64
Discord notifications have been added to v3.
Most helpful comment
Note that this is achievable right now, using the Slack connector, and Discord's Slack-compatible webhooks.
Simply generate a webhook URL for a Discord channel per the documentation, and add
/slackon the end. Then setup the Slack connector as you usually would.To this end, does Sonarr need a Discord-specific connector? What additional functionality would it provide?