Some users have asked me to install the mosaic package (www.mosaic-web.org/mosaic/) in our conda setup, but I cannot r-mosaic anywhere. I do find r-mosaiccore and r-mosaicdata but this is not sufficient according to my users. It is on CRAN, but having something prebuilt is always preferable.
It is now available through Conda Forge, i.e.,
conda install -c conda-forge r-mosaic
In the future, it would be better to submit a package request Issue to the Conda Forge staged-recipes repository when there are packages that you would like added.