In 16" rim size, the following upsizes would be possible :
Please keep in mind that as you go for wider tyres, the readings of odometer and speedometer get altered. Wider tyres would show more kilometres on the odometer than actual. Also, with wider tyres, the steering might feel a little heavier due added weight of the rubber. And since heavy tyres would require more energy to be brought into motion, the fuel efficiency of the vehicle and tyre life will also decrease by a some margin.
On the upside, the braking efficiency would improve and vehicle stability would increase.