I've got an old Lenovo Tab3 850M table, running Android 6.0.1
It's pretty vanilla and I haven't installed any custom ROMs or rooted the device.
The battery is in pretty good condition and the table can idle for around a week I think.
It has an 8 inch IPS display, Quad-Core 1.0GHz ARM Cortex-A53 CPU, ARM Mali-T720 MP2, 500 MHz, 4-Cores GPU, 2GB of RAM, and 16GB internal storage.
The cameras are pretty terrible (even for 2016 standards), and the battery is 4300mAh.
Android 6 and 2GB RAM are still pretty sufficient, that should run everything important. I'd try to flash some lightweight ROM (maybe with higher Android) or at least debloat, and just use it normally for whatever I'd use a tablet for.