AZInsight from AsinZen is a Chrome-based Amazon product research tool with a profit calculator, sales estimation, product hazmat and restriction checker, and branded product avoidance.
AZInsight also includes a product variation viewer and stock checker. All features are displayed directly within Amazon pages. AZInsight allows multi-user access and has its own add-on marketplace.
$59.95 for a lifetime subscription.
Or from $59.95 to $149.95 per year.