Multiple Slack Teams
Slack is the best tool for team communication now but there is no easy way to have several Teams open simultaneously.
SlackDeck is a simple tool that allows you to open as much Teams as you want.
Tip: To rearrange tabs, just drag one on a position you want.
Not affiliated with Slack.
1.1 - change "Add new tab" button appearance. A window will remember the size and its position and restore the state later.
1.0 - Initial release