Plenty of languages (commercially) target the CLR, however given its Windows focus, many UNIX FOSS based researchers never cared about it, even in the presence of mono.
Microsoft abandoned IronRuby and IronPython around 10 years ago. Meanwhile TruffleRuby on GraalVM is the fastest Ruby implementation by far.
From Microsoft itself, F**, F#, VB.NET, C#, Sing#, System C#, Managed C++, C++/CLI, Cω, Axum, and who knows what else they have done internally.
From Microsoft partners, COBOL, Eiffel, Ada, Fortran.
From FOSS community and university researchers, not so much because it is M$ and better not use Mono because of patents, so was the saying.
That means the DLR is effectively dead, I think -- along with all languages for which the CLR's static call sites mean slowed performance.
Plus on UNIX, Java has 25 years of history, not 4 (not counting WIP mono here).
I spent most of last year maintaining a Web Forms app. It's no fun. Ironically, there used to be many more CLR languages, because Microsoft paid for their development. IronPython and IronRuby stand out. I wish ClojureCLR weren't dead too.
Is there any reason for saying that? Checking the commits history on Github[1], the project seems still alive.
Either way it's pretty clearly not a core platform for Clojure.
A google search would tell you otherwise.
https://groups.google.com/g/clojure-clr/c/2v9xls5hreE
Last commit 6 days ago: Last code change 11 days ago: https://github.com/clojure/clojure-clr/commits/master