Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
ApproveIt for Slack - Get approvals in minutes, not days. Right from Slack!
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
AccessOwl - Discover Shadow IT, Automate Access Reviews and Auto-Provisioning — No Enterprise-Subscriptions required.
eM Client - eM Client is a fully-featured email client for Windows and macOS with a clean and easy-to-use interface. eM Client also offers features for calendars, tasks, contacts, notes, and chat.
Approve app for Zendesk - Any enforceable and auditable approval workflow for Zendesk tickets you can imagine can be easily created using the Approve app.