While setting up this website and collecting information, I found a (relatively) small number of freely available sources.
In this article I will share them with you. Do you have additional sources? Let me know by using the contact form.
Free trademark information
Let us start with two projects of the Wikimedia Foundation: Wikipedia and Wikidata. They contain a lot of useful information. We help them as well, read our article How does genericides.org give back to the community?
Gary Hoover collected a list of "most powerful brands", from the year 1923. https://data.world/garyhoov/most-powerful-brands-1923
The Open Knowledge Foundation maintains a "open product" list, with an overview of all products manufactured by a certain company https://product-open-data.com/owner/list
Similarly, you have icecat, a worldwide unique open catalog with product data-sheets https://icecat.biz/
Lastly, you can use the data of the USPTO, including the results and conclusions from the trademark trial and appeal board https://developer.uspto.gov/product/trademark-annual-xml-ttab#product-files This is of course only for the US market
There are a lot of other, paid, options available: Young and Rubicam’s BrandAsset Valuator, Interbrand, and the American Customer Satisfaction Index. I will discuss them in a later article.
Do you have interesting sources you want to add? Let me know via the contact form.