All 89 bee plants
Ling heather pollen
Calluna vulgaris
Whitish cream, in the cream / white range.
FloweringJuly to September
PollenFair
NectarYes
SeasonSummer, Autumn
WhereMoor and heath
The classic heather honey plant, thick and jelly-like in the comb.

Easy to mistake for these
Closest pollen colours in our set, measured the same way the pollen identifier scores a match. Colour alone will not settle it, so check the flowering months and what is actually growing near your hives.
Out at about the same time
Saw a load like this going in?
Sample the colour against all 89 plants, then keep a forage record per hive.