Guile is the 'official extension language' for GNU projects; i.e. for embedding into C programs, for scripting, macros, writing plugins, etc. This gives it a boost in popularity (similar to how JS got a boost from being the 'official extension language' of the Web; although on a massively different scale!)

Looking at https://en.wikipedia.org/wiki/Common_Lisp#Applications I've personally used StumpWM and ACL2; and Cyc is a rather prominent project.

One notable application that's written in Racket is Hacker News! (It's written in 'Arc', which is implemented using Racket).

Oh yeah I think I should add that it was certainly not my intention to downplay the more popular lisps or their applications!

Not sure at which extent they still use Common Lisp, but syscog used to be a Lisp shop for their transport and trafic management software.

https://www.siscog.pt/en/

https://franz.com/success/customer_apps/scheduling/siscog.lh...

Google also became a Lisp shop when they acquired ITA

https://www.nytimes.com/2010/07/02/technology/02google.html

https://franz.com/success/customer_apps/data_mining/itastory...

Apple, Walmart, Baresquare, Nubank use Clojure

https://www.cognitect.com/blog/2015/6/30/walmart-runs-clojur...

https://jobs.apple.com/en-us/details/200184362/apple-media-p...

https://www.baresquare.com

https://nubank.com.br/en/

I think that this is a situation where the former are all server-side tools used beneath the surface to power that SaaS used by millions every day, while the latter is visible in a small handful of tools used only by the tiny fraction of the population that would visit sites like HN and even then Guile is used (statistically speaking) by no one.