To do Alt + h l t t on Mac in Excel, download and install Accelerator Keys, then press Option, followed by h, l, t, t.
Command: Format Top 10 Items
This is how to do Alt + h l t t on Mac in Excel with Accelerator Keys, the native ribbon and alt key shortcut solution for Mac users who get more done with Excel.
Alt + h l t t highlights the top 10 items (by value) in your selection. You can change the number of items to highlight.