FIRST - Post a date, pick a winner & meet up.
OKRStudio - Connect Trello cards to OKRs. Manage OKRs inside of Trello
Marketing Teams and Slack - A handbook for marketing teams to make the most out of Slack
OKRs.app - Reach your personal goals with OKRs
Startup Marketing Playbook - The how-to guide for new B2B marketing leaders
Perdoo - OKR methodology, software and coaching