Nebula is an open source Discord Bot currently being developed by @zephanrs. There are a variety of features, with more planned to be added later this year. You can use this invite link to invite Nebula.
Nebula is still in early development. Expect long down times, and limited features. The bot is currently self-hosted, and will be until it is in a polished state.
Feel free to add my discord zephans#5657 if you have any questions or potential contributions.