Gruntwork Runbooks is a free, local desktop app for platform golden paths. Runspace adds separate-reviewer approval, locked revisions and an audit log.
PagerDuty Runbook Automation is mature, job-based automation built on Rundeck. Runspace is a pre-launch notebook-style runbook tool with per-run reviewer approval.
Rundeck runs scheduled jobs across nodes with an open-source core. Runspace runs notebook-style runbooks with per-run approval by a separate reviewer.
Runme is free, open-source notebooks for runnable Markdown docs. Runspace adds per-run approval by a separate reviewer, reviewed revisions and a server-side audit log.