Sortd - Rated the #1 App for Gmail
Jama Connect - The Leader in Requirements Management Solutions
KanbanMail - A Kanban board for your emails.
ReqView - Simple and powerful requirements management tool enabling easy requirements gathering, traceability tracking and offline collaboration.
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.
Enterprise Tester - Test Management and QA software, offering: full tracability, rich and indepth reporting, integrations with the likes of Atlassian Jira and an extensive API