Power BI Slicer is a great tool to customize reports, but it can be difficult to use with long lists.  One way to fix this is to use two slicers as a hierarchy to speed selection.

Here is an example.  The product list in AdventureWorks is long.  Here is a report that show the Inventory and the pricing for a product selected from the slicer.

The lit is long and its difficult to scroll up and down to find the product one is looking for.  One way to speed the search is to add a hierarchy.  I chose breaking things up by the first letter in the product name.

To do this, I edited the product table by copying the Name table.  Then i split the copy of Product Name into to two columns, with the first letter as the first column.  Then I renamed the column Name A-Z.

Now add a second slicer using the Name A-Z.  Now you can select the first letter of the product you want, then select the product from the filter product list!  Much easier than scrolling away!