iPad Air (Original Model)
The original iPad Air is another tablet you should cross off your list.
The first-generation iPad was released all the way back in the fall of 2013. The device currently runs iOS 12.4.4, but like the iPad mini 3, software support has slowed down.
Again, this is a big deal because it means a) you won't get regular bug fixes from Apple and b) you won't be protected with all of the latest security patches.
They've got better hardware and all three models have been upgraded to Apple's iPadOS 13 operating system.