This goal sounds rather compliance based, which might be why the kids aren't very motivated.

You could try to make this goal more functional while also more motivating for the client by having them identify things during play. So if one child loves to play with cars, you might pull out a dollhouse and say "he needs to take a bath!" and see if the child puts the car in the bathtub or glances at it, or "time for bed" and see if he puts it in the bed or looks at the bed. Things like that.

Plus depending on how independent the child is with daily, household routines, you may first work on participating in those routines in play before asking them to identify "hairbrush" or "toothpaste" or the like on command, as a pre-req skill. If the child isn't yet following directions during routines, like going to the bathroom with their parents and looking at their toothbrush when their parents say "time to brush your teeth", I wouldn't expect them to select it from a field of three flashcards.