Shells run "on top" of DOS and (although they have the capability of opening a CLI Window) are primarily intended to utilize only their own Exclusive Shell Applications.

Graphical User Interface

Costa GUI (ver 1.8.0) - Freeware

[GEOS] Ensemble (ver 4.1.2) - Abandonware

FreeGEM (ver 3.2.3-paac10a) - Abandoned Freeware


NOTE:
It is very strongly urged that persons seeking a Graphical User Interface Shell avoid the Windows 3.x Shell for DOS. The Windows Shell is rather buggy, engorged with software bloat, and a huge resource hog. If there is absolutely no regular DOS alternative to a Windows Shell Application, the superior solution is to run the App under OS/2 (which incorporates an excellent integrated Windows 3.x interface).