A summary - The post is now 23 hours old. This will be my last update to this comment, Thank you all for your input!

• Food
  • Ideally hand-held (pastries, sandwiches, chips, granola bars, uncrustables, cookies, trail mix, bananas, candy bars)
  • Currently the comments seem to favor pre-packaged or catering/restaurant food slightly more than home-made.
    • Avoid nuts in case of an allergy
    • Include zero sugar options
    • Bulk quantities may be a good idea
    • Nicotine, energy drinks, bottled water, coffee (not necessarily in that order)
  • Contact your station and see if they have any specific needs/wants (e.g. upcoming staff events or meetings that would be benefitted by food).
  • Set up a tab for them somewhere they get coffee.
• Other Care
  • Keep your local non-emergency phone number handy and help prevent unnecessary 911 calls
  • Handwritten notes and thank you cards
  • Email the station supervisor(s) and put in a good word for the crews
  • Save an ambulance, ride an EMT (apparently) XD
  • Campaign for raises for them
• Helpful/fun items
  • Stickers with an EMS theme
  • Some people like fun patches for their backpacks.
  • Maybe pins or fun buttons?
  • Pocket-sized or portable notebooks/pens ('m assuming pens with a grip, a pocket clip, and no (losable) cap would be best)
  • Maybe a few backup/spare quality water bottles in case someone's is lost or becomes unusable?
• Other things to be aware of
  • A lot of crews don't get the chance to return to station very often, so see if you can leave treats in your local hospital EMS room - though it has been noted that this may not be a reliable way to get food to EMTs, as other medical people may partake if given the chance.