This is a specifically created Community Wiki which gathers resources for learning English and it has been approved by the Community itself.
It should be clear that the resources are not written by one user or only by the mods, but by whoever wants to contribute.
Just write in the appropriate answer/section. If you have questions or concerns, ask a Meta question so we don't clutter the comments. You can link your Meta question from the comments.
Questions regarding such resources are still allowed, but they will be closed as a duplicate of this question if they are too broad. Specific and on topic requests are welcome (ask on Meta if you're unsure about your question). Follow the instructions made in the question about how to post, what can be posted, etc.
- Each answer contains only one type of resource, and all resources of that type.
- If possible, state whether the material is directed towards a beginner, intermediate or advanced audience.
- Do not include links that lead to illegal content or sites that host such content. If you see any, please flag for moderator attention, select other, and specify the offending resource. It will be deleted as soon as a moderator sees the flag.
- Follow the community rules on self-promotion.
- Please indicate whether each resource is free or paid and if registration is required.
- Do not post images. They would take too much space.
- Use descriptive links instead of bare URLs where possible.
- Add resources in alphabetical order so that they will be easier to find. Resources starting with non-Latin characters should go after the end of the alphabet.
Note: New rules could be added in the future. Please ask a Meta question if you think a rule should be added, removed, or changed.