Sure but these companies develop mission-critical software applications in Haskell. They are not open source for the most part, but in terms of demonstrating that Haskell is practical they are good examples.

They're just names of companies, which aren't very useful as demonstrations. If you could describe some particular problems these companies have solved in Haskell, then that would certainly be useful.

Facebook is using Haskell to control spam.

https://code.facebook.com/posts/745068642270222/fighting-spa...

Galois uses it for their financial products,

https://galois.com/about/haskell/

A German company, CMED, uses for their medical services server

http://cpmed.de/jobs/haskell/

Other than that, not all companies are found of putting all their golden eggs on Github.

Galois does not work on financial products. It is a research services company (i.e. R&D for hire) that focuses on high-assurance software.

i believe Lumi (YC company) uses Haskell for its backend https://news.ycombinator.com/item?id=12732592