OKRStudio - Connect Trello cards to OKRs. Manage OKRs inside of Trello
Trivia for Google Chat - Team-building w/ fun quizzes, games right inside Google Chat
OKRs.app - Reach your personal goals with OKRs
Social Games in Slack - Polly brings your WFH team together with interactive games
Perdoo - OKR methodology, software and coaching
Flinkit! - Web-hosted team building games for small and large companies