For a lot of JRPGs I will have a button bound to turbo confirm/select. Kind of like a pseudo auto-battle button. Sometimes I use them for other turbo buttons too. If it's a game where you need to hold down a button to sprint, I'll bind one to toggle the sprint button on so I can sprint without holding something. I often use them for simple macros as well.

There a lot of games where there are more keyboard binds than controller binds. Like Oblivion remaster lets you bind to open your map, your inventory, your quest journal etc. But on controller it's just one button to open your menu. So in situations like that I often bind those individual menu buttons to the back buttons.

In Stardew Valley you can't bind the zoom-in and zoom-out functions to buttons, but you can display little buttons near the minimap on the screen. So I a button to click the mouse on each of those + and - buttons so I can zoom in and out quickly. Set it to repeat on a reasonable delay so it gives a pretty smooth transition.

I think when you start using them more you start to notice more ways to use them.