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.
If you have an older scanner, use it for the stuff above to supplement your P25 Phase 2 scanner (if you have one).