Trello - Infinitely flexible. Incredibly easy to use. Great mobile apps. It's free. Trello keeps track of everything, from the big picture to the minute details.
Slack Jira Integration - Easily keep issues moving right from Slack
Agile Tools for Trello - The one power-up all agile teams using Trello need
Sortd for Slack - Get Trello-style project boards right in your Slack!
Elegantt for Trello - The most elegant way to manage your Trello projects
Actions from Slack - Turn Slack messages into tickets, issues, tasks, and more.