Are you looking for something made up of veterans or supporting veterans? Here is an example of each that I like:
"The Mission Continues" has a Dallas platoon which consists of veterans who want to
give back to the community. My company is a corporate sponsor so we partner up periodically on their service projects, the most recent one being a school revitalization, and one later this month to clean up and help work on horse stables at Equest that are used for equine therapy.
Another that I volunteer regularly with is "Allies in Service" who supports veterans hiring, this is great if the volunteer has hiring experience. Volunteers are needed for editing resumes or giving mock interviews. This is especially helpful to break down the military lingo and translate it to corporate speak.