NOAH
From Just Solve the File Format Problem
NOAH (also called NOAH's archive utility) is a file compression utility for DOS, and its native compressed file format. It was developed by Richard Levey, and distributed as shareware.
Format details
Files start with a 4-byte header giving the original file size.
NOAH v1.1 format seems to be identical to Okumura's LZARI (modulo LZARI's non-portable header).
Version 3.0 format is not the same as v1.1.
Identifiers
The software does not provide a default filename extension. The v1.1 documentation suggests that you could use .noa.