silver530

This plugin allows you to make simple to-do lists for task management. The plugin comes with custom post type allowing you to organize your lists by filtering categories. Whether you are planning an adventure, going to shopping or simply keeping track of your daily to-dos. Also comes with a custom widget allowing you to show lists in any widget location or sidebar.

BossList

Task management system inside WordPress admin.

adridi

A calendar that improves the user experience on your website. 
You can change the style and language of your calendar widget in the WordPress settings (“Design” -> “Widgets”). 
The calendar is responsive which makes it suitable for all type of devices.

Responsive Calendar Widget

A responsive and simple calendar for your Wordpress website. It is interactive and you can change the style in your Wordpress settings.

BossList vs Responsive Calendar Widget