By default slicers can display a limit of 50,000 elements. For performance and usability reasons, you may want to decrease the maximum number of elements that can be displayed in the slicer. The limit can be decreased from the user settings tab; this will change the slicer limit for all slicers for the current user. You can also change the limit per slicer, from the slicer settings dialog.
The limit must be a number between 100 and 50,000. A slicer limit set from a slicer's settings dialog cannot be greater than that set from the user settings.
If the slicer hierarchy contains more elements than the limit that was set, you can search for those elements from the slicer.
Slicer Limit Indicator
If the number of elements in the slicer hierarchy exceeds the elements limit, a 'limit indicator' will be displayed:
You can hover over the indicator to see what the slicer elements limit is: