Best Extension to Suspend Inactive Tabs

Tab Manager puts tabs you haven't looked at for a time you choose (15 minutes to 4 hours) to sleep, using Chrome's own tab discarding, and they reload when you click them. You can keep chosen sites awake with "Sites that never sleep", pinned tabs stay awake, tabs playing sound are never slept, and Alt+Shift+S sleeps every other tab at once. Chrome's Memory Saver (Settings > Performance) does similar work with less control over timing, and has its own keep-active list. Sleeping a tab can lose anything typed but not submitted on that page.