ERI (compressed archive)
ERI, or Eri32, is a compression/archiving utility for DOS, and its associated .ERI file format. It was developed by RAO Inc. and/or Alexander Ratushnyak. It is promoted as a "multimedia archiver" (a term that probably means something to compression experts).
It is closely related to ARI. The exact nature of the relationship is not clear, but ERI is newer.
ERI format seems to be nearly identical to ARI format in structure, but with the filename padded with NUL bytes instead of spaces. The compression is incompatible.
Pointers to other versions might be found by searching for documents named "The Art Of Lossless Data Compression" (e.g. these archives of geocities.com/eri32/).