Crossmeta NFS Services from Pavitrasoft — proprietary.
Cygwin NFS Server and Client — open source under GPLv2.
DiskAccess (client) and DiskShare (server) by Shaffer
Solutions Corp. LLC (formerly from Intergraph Corp.) — proprietary.
Distinct NFS Server by Distinct Corp. — proprietary.
InterDrive Client 4.0 for Win95/NT by NetManage, Inc.
(formerly FTP Software) — proprietary.
Microsoft Services for Unix (formerly Interix from Softway
Systems, Inc.) — proprietary: gratis download, for MS-Passport users).
NFS for SmarTerm from Esker Software (formerly Persoft) —
proprietary, apparently discontinued.
nfsAxe from LabF (gratis download, proprietary, US $40 to
NFS Maestro by Hummingbird Connectivity Technologies,
Inc. — proprietary.
Omni-NFS by XLink Technology, Inc. — proprietary.
PathWay Client NFS by Attachmate Corp. — proprietary, apparently
PC-Xware by PCD — proprietary.
ProNFS by Labtam Inc. — proprietary.
Reflection NFS Client by WRQ. — proprietary.
Rumba Office 95/NT for TCP/IP by NetManage, Inc. (formerly
Wall Data) — proprietary, apparently discontinued.
Solstice Network Client for Windows from Sun Microsystems, Inc.
— proprietary, discontinued; firm recommends WRQ's Reflection NFS
SOSS-NFS (Son of Stan's Server NFS) — open source under GPLv1.
SuperNFS by Frontier Technologies Corp. — proprietary.
Term Professional by Century Software — proprietary, apparently
War NFS Daemon by Jarle Aase (now unmaintained) —
proprietary, gratis usage for non-commercial purposes.
Alternative: Use Samba. (Most people trying to do NFS on MS-Windows are solving the wrong problem.)