At the moment I can think of 5 things besides unique species characteristics.  Please note though that it will help you to consider exactly what species you wnat to focus on to see if individual speicies have more useful unique characteristics. Monkey have hands; mole (ok insectovore) burrow; etc.

1) Number:  Because plant life is much easier to produce enmass than meat, expect that the biomass of herbivores will greatly exheed that of carnivores.  For every lion, you need many zebras.  They are very good at stampeeding.

2) Size:  While not the majority, the most giant beasts tend to be herbavores.  Ignoring elephants and rhinos for now, there are large numbers of large grazing mammals such as bulls that can do some serious damage in they put their weight into it.

3) Repurposed defense:  Herbavores are evolved to survive carnivore attacks.  Obvious examples include horns and hooves but for strategic purposes, poisons or spines could theoretically serve a purpose.  If they are good enough to defend, they are usually good enough for attacking.  They could also help to slow advancing forces by standing their ground.

4) Repurposed escape:  Some herbavores survive not by defending themselves but by getting away.  This means they might be good for reconnaissance but are generally outclassed as far as this goes by falcons and what not.  They may, however, be able to move quickly and not be seen.  A mouse is great at hiding and spying.  A sparrow can get in and out quietly and quickly to pass the info on.

5) Insight riots:  Finally, you can use the carnivore/herbavore thing to your advantage.  While the pure carnivore enemies plan their war, the more allied forces sneak into enemy territory and speak to the other herbavores.  "Hey dude, I'm like you but it is better over where I'm at.  Help us out and it will be better here."  Let the monkey and hare then release all the cattle.  The rooster than calls loud enough to signal the other camp to go forward and all hell breaks loose.