This online calculator uses math to
calculate the exact win probabilities and average length of battle in number of attacks (which is the same as number of half turns in the absence of multiple attacks, frenzy, or squads). The average survivors is the average number of life or figures left assuming that the figure or squad wins.
If you are lucky enough to have acquired HeroScape terrain, you may be interested in these Colonial Rules For Heroscape terrain.
Wargaming Miscellany has a post on modifying Heroscape hex tiles.
Here’s a high resolution pdf file with the stats from all Heroquest figures through Wave 6. Printed out, it would make a handy reference sheet.
Solidscape is a bit of software that converts Heroscape maps created with Landscape into fabulous looking 3 dimensional view.