The Finder’s Customize Toolbar dialog sheet (that’s what it’s called when it slides out of the title bar!) – open it with View > Customize Toolbar – provides two adjustments for how your toolbar icons look. There are six combinations of the two controls: Show (Icon & Text, Icon Only, or Text Only) and a checkbox for Use Small Size. Cycle through them without opening the dialog by Command-clicking on the toolbar button in the upper right of the window.
TIP: Cycle through Finder-window toolbar display options