You will be missing out on a lot if you don't have a P25 Phase 2 scanner, but there is still some stuff to listen to:
-DPS - Nothing beats a good chase.
-Mutual Aid Frequencies - If there is a major event that involves multiple agencies, these will probably be active.
-Air Evac Helicopters- I'm not sure how active they are in Tucson, but there is a lot of activity in Phoenix.
-Northwest Fire/Rescue - It looks like they are still analog. I'm not sure how active they will be.
-Forestry and wildfire frequencies
-Civilian Aircraft - A lot to monitor.
-Military Aircraft - If you are around Davis-Mountain AFB, there is probably a lot of Mil Air activity.
-Customs and Border Patrol - If you have a P25 Phase 1 scanner, add the frequencies. It is mostly encrypted, but you will sometimes catch some in the clear.
-Businesses
-Schools
If you have an older scanner, use it for the stuff above to supplement your P25 Phase 2 scanner (if you have one).
Happy Scanning!