https://wordpress.org/plugins/wp-content-calendar-lite/ - A drag and drop content calendar for WordPress. You can literally drag and drop posts to different dates on a calendar and they'll post automatically when the date comes round.

I built it last year, along with a premium version (which auto-suggests what you should write based on low competition kW opportunities) but ended up not getting around to releasing it. The free plugin is up on WordPress and has about 700 downloads.

I'm willing to sell the free + (unreleased) premium plugin for the right price.