clusterCrit
In words of the author of the package, Bernard Desgraupes, whose personal webpage https://bdesgraupes.pagesperso-orange.fr/ is accessible through Internet Archive.
This package computes clusterization quality indices. It supports 42 internal indices (Calinski_Harabasz, Dunn, Ray_Turi, etc.) for cluster validation and 14 external indices (Phi, Jaccard, McNemar, etc.) to compare partitions.
A vignette is included and gives the exact definition of all the indices.
The package is written internally in Fortran and in C so you will need a Fortran and a C compiler if you want to compile it from sources. Alternatively, there are already compiled binary versions on the CRAN mirrors.