TL;DR
Have multiple items associated with a toolbar slot, switch to the other items in the group with ctrl+scroll.What?
Allow having multiple items in one slot in the toolbar. When setting filters for the toolbar, allow multiple selections. Then, when using that slot from the toolbar, be able to switch between the items in the group by using ctrl+scroll (similar to scrolling between blueprints in the blueprint book).
Why?
No more inserters taking up 3+ spots on your toolbar! By making a group for inserters, you free up valuable space on your toolbelt. You still will always have access to other inserters with just a ctrl+scroll away. This can be expanded to many useful groups, such as:- belts
- splitters
- undergrounds
- assembly machines
- poles
- turrets (+walls too, if desired)
- circuit equipment
- railroad equipment
- and so on!
I chose ctrl as the modifier for switching between item groups. That way, there is still functionality with blueprint books and blueprint pages. Ctrl allows the user to switch between blueprint books, and shift allows for switching between blueprint pages in the selected book.
Also, please view this link for more ideas to expand upon this: Toolbar Flyout For Selection of Subtype of Objects
Credit for original idea goes to Hexicube on the /r/factorio Discord server.