Royals = 509th Bomb Wing at Whiteman Air Force Base outside of Kansas City, MO.
Cardinals = Maneuver Support Center of Excellence at Fort Leonard Wood Army base in central Missouri.
Padres = San Diego Naval Base
Reds = 88th Air Base Wing at Wright-Patterson Air Force Base near Dayton, OH.
Brewers = Fort McCoy Army base near Tomah, WI
Marlins = U.S. Naval Forces Southern Command at the Mayport Naval Station near Jacksonville, FL.
Rockies = 460th Space Wing at Buckley Air Force Base outside of Denver, CO.
Dodgers = California Air National Guard at Ventura County Naval Base outside Oxnard, CA.
Yankees = West Point Military Academy in New York.
Army hats were given the new Army Combat Uniform pattern, the Air Force got the Airman Battle Uniform or Tiger Stripe pattern, and I went with digital Battle Dress Uniform for the Navy.
If the base itself had a patch and it looked cool, I'd use that, but in most cases I used the patch from the base's host unit. That made sense to me, because for many teams the host unit of a nearby base handled flyover duties at the stadium, which made the partnership feel right.
In some cases, like the Dodgers, I kinda picked a patch that only semi-made sense simply because it just looked real cool, with the caveat that this was simply a proof of concept.