AAAAAAh
I see what you mean ... not the filter contents .. but the filter options ... sort, all, top10 and custom etc?
The only way I know is to increase the zoom on the sheet
menu | view | zoom | 200% (or whatever)
this increases anything on the sheet.
Another possibility is to alter the desktop properties
Control Panel | display | settings | advanced | general
and
Control Panel | display | appearance | Advanced
and play with the settings ... but this is a global change