The only single cell battery testers I’ve found thus far focus on standard primaries from AAA to D, plus 9V. Some look pretty decent. But I’d like to find one that is capable of testing 16430, 18350, and 18650 cells (possibly 26650). Does any such tester exist, beyond a full featured multi-meter?
What sort of properties do you want to be able to test? If capacity is one of them, then what discharge rate do you want to test up to? And what’s your idea of a modest cost for this sort of thing? $10? $100?
ZTS has some: Test/review of battery tester ZTS Mini-MBT
But for LiIon a multimeter is better, you can see some voltages here:
https://lygte-info.dk/info/BatteryChargePercent%20UK.html
For best precision get a 6000 count multimeter, I have tested some meters here: Index of reviewed multimeters table