An Hour of Wolves and Shattered Shields has a set of free printable decals for Ancient Greeks. You can print these on decal paper, or on regular paper and glue them to the models.
An Hour of Wolves and Shattered Shields has a set of free Roman Shield designs for decals. Just print them out on decal paper, or on regular stock and glue them to the models. I should think that a hobby product called Modge Podge would handle that task well.
Dale the Wargamer offers a set of free Ancient Campaign rules
A Meeting of Hosts is a set of rules for simple ancient wargames with toy soldiers by Ross Macfarlane, inspired by Joe Morschauser and Don Featherstone.
Wargames Rules For Classical Warfare is a set of free wargames rules by David Wareham. They are designed for playing games set in the period from c. 500 B.C. to c. 700 A.D. The rules use an alternate
movement system and whole figure casualty removal. They are primarily designed for use with 15 and 25mm figures.