SnowSoftware - Snow Software are suppliers of Software Asset Management products and help optimizing licensing & minimizing compliance risk.
Stockpile - Stockpile is a free online inventory system for small business and at home uses.
Torii - SaaS Management Software.
Snipe-IT - Managing assets with a Google doc or a shared Excel spreadsheet is more common than you think.
SoftwareKey Licensing System - SoftwareKey System is a set of software development tools that help programmers implement copy protection, license activation and management, metering, eCommerce, and business automation.
PartKeepr - PartKeepr is an open source inventory management system that you can alter according to the particular requirements of your business or of the area from where you are operating.