White eneloop - medium internal resistance, large number of discharge cycles.
Black eneloop - small internal resistance, fewer discharge cycles. Less resistance, means more current, so better for cameras or automatic arm or wrist blood pressure monitors.
Orange green eneloop - high internal resistance, high number of discharge cycles. Very good for mice, keyboards, cordless phone handsets (no range problems like cell phones).
There were also series in other colors, but intended for less demanding applications than white or black.
Recyko makes similar batteries. White ones quite long-lived, quite powerful, quite capacious. Black ones with less resistance and green ones with a little more internal resistance than white ones. It is worth noting the self-discharge current. Now the batteries can lie for several years and will not discharge. You do not have to watch them to make sure they do not spoil from too deep a discharge during storage.
I will also mention NiMH accumulators in sizes R14, R20. These are also like that, also have a lower self-discharge current, although not as low as Eneloop (Panasonic now) or REcyko (GP).