This little Hermit Shell case fits the TL866ii perfectly (tight)

https://www.amazon.com/Hermitshell-20000mAh-Portable-Charger-External/dp/B01N2Y8WTJ

Or this one if you prefer a little color. It’s also about 1/8” thicker so not quite as tight

https://www.amazon.com/Hermitshell-Travel-Fujifilm-Smartphone-Printer/dp/B0825KZRM9

I also tried a Case Logic TBC-403 soft camera case. It’s a great fit too and you could probably stuff it into a tighter space if needed but maybe not as much protection as those firm-shell cases.