This free Reddit thread tracker can monitor multiple subreddits in real time at one place and update every 90 seconds. Add up to 8 subreddits at most and choose to save automatically. You can filter and view recent posts by time windows such as 5 minutes and 15 minutes, and you can filter by keywords by opening the advanced settings. You can choose to "only show" or "hide". You can also add keyword highlighting to mark important content. Visited posts have a tick mark and change color, and new posts have a "NEW" label. The tool automatically refreshes the content.