Here are some ideas:
New Unit: ALS Engine, this unit is an engine that can also treat patients 90% (or 100% PLEASE!!!).
New Call: Caller Hangup, this call will be 1 patrol car and 1 Engine. This could get upgraded to domestic dispute, any of the medicals, or residential fire, and it could not upgrade, and have a prisoner.
New Feature: In the unit editor for the quints and rescue engines, have it be dispatched as only a rescue/truck, only as an engine, or both. (I need this, please!)
New Unit: Mass Casualty, this unit will treat all patients on a call, but will not transport.
New Unit: Rescue Quint, This is a rescue, a truck, and an engine. (EVERY truck in my department is a medium rescue and is a quint)
New Call: Drowning, this call will require 1 engine, 1 ambulance and 1 battalion chief.
New Call: Unknown medical, this call will require 1 ambulance.
New Call: Automated medical alarm, this call will be 1 ambulance. (like LifeAlert)
New Call: Suicide, this call will be 1patrol car, 1 engine and 1 ambulance.
New Call: Possible DOA, this call will require 1 patrol car, 1 engine, and 1 ambulance. (My department gets this type of call a lot more then you think, usually at least once a week)
New Unit: Dozer/Bulldozer.
New Call: large field fire, this call will require 3 engines, 1 water tanker, 2 battalion chiefs, and 1 dozer.
New Call: Large wild fire, this call would require 7 engines,3 water tankers, 3 battalion chiefs, 1 MCV, and 1,2 or 3 Dozers.
New Call: Possible drug lab fire, this would require 4 engines, 2 trucks, 2 battalion chiefs, 1 MCV, 2 hazmat, 4 patrol cars, and can have up to 10 casualties.
New Call: Kidnap, this call will require 4 patrol cars and 1 SWAT, has 1 casualty.
New Call: Lost child, this call would require 1 patrol car and 1 ambulance, has 1 casualty.
New Call: Smoke investigation, this call would require 1 engine, 1 truck, and 1 battalion chief, and has a 55% chance to upgrade to any fire
New Call: Cooking fire, this call will require 1 engine and 1 battalion chief, and have a chance to upgrade to commercial fire or residential fire, and could have 1 casualty.
New Call: Trapped in elevator, this call will require 1 engine, 1 truck, 1 heavy rescue, and 1 battalion chief, and can have up to 4 casualties.
Note: All of these unit and calls exist in my department, and all the calls are much more common then building collapse, gas station fire, stabbing, active shooter, and any of the aircraft calls...
(That being said, I really to like the previously mentioned calls, especially the airport calls.)