There are map templates for GSC (Guild System Campaign). You've probably created and tried playing on standard templates. They are quite basic. Also, there are custom map templates created by players. There are various and quite interesting templates. Including my own template :) There are also special mods for GSC in Heroes. They fix such shortcomings as non-functional roads on snow, the absence of wells, mana springs, etc., and change other things. As a result, GSC creates quite diverse and interesting maps using these templates and mods.