Seald - Keep your conversations secure, everywhere.
Trello for Slack - Organize anything with anyone, inside Slack
Crypho - End-to-end-encrypted messaging and file sharing
Intercom - Intercom is a customer relationship management and messaging tool for web businesses. Build relationships with users to create loyal customers.
Spike - Spike solves businesses' communication chaos by bringing together email, team chat, collaborative docs, and meetings, into one feed.
Halp - Slack-first ticketing for internal helpdesk