Serpstat - Search analytics, Rank tracking, Backlink analysis and Site Audit tool.
OpenVoyce - Openly discuss and vote on ideas, opinions and reactions
Topic Research by SEMrush - Content ideas that resonate with your audience
Scrivener - Scrivener is a content-generation tool for composing and structuring documents.
Answer Socrates - Discover content ideas using real Google data
Lampant - Helping organizations find and act on the best ideas