If you want to contribute to this list (please do), send me a pull request. Since we want this list to be useful in the long run, **please submit high quality links only**.

## Adding to this list

Please ensure your pull request adheres to the following guidelines:

- **Please make an individual pull request for each suggestion.**
- The pull request and commit should have a useful title.
- Please search previous suggestions before making a new one, as yours may be a duplicate.
- Make sure your link has a useful and relevant title.
- Please use [title-casing](http://titlecapitalization.com) (AP style). 
- Please use the following format: `[Useful Title](link)`
- Link additions should be added to the bottom of the relevant category.
- New categories or improvements to the existing categorization are welcome.
- Please check your spelling and grammar.

Thank you for your suggestions!