How can I find company descriptions for a long list of companies?

I'm going to train an ml algorithm to qualify potential sales leads based upon company descriptions. To do this, I need to find the company descriptions programatically.

E.g. given a long list of company names, how can I find descriptions for these companies. Here are my current techniques, which works ok, but not great:

• Using Google Search API to and fetch summary from the results page (Google normally gives the company website as the first result when searching by company name)

• Fetch all data from the company's website (includes an about-page and a lot of other less relevant data)

• Using the FullContact Company API to get any descriptions the company has on its social profiles (works great if the company has an online precense)