TL;DR
When you have an Assembler/chemical plant/oil refinery selected, have a left arrow and right arrow (or press left and right arrow) that moves the view focus to the next machine with the same settings.What ?
In multiplayer games and old save files, the player doesn't always know where all of the buildings making a certain product are. Being able to cycle through all of the buildings making (for example) green circuits would be helpful in counting how many there are and making sure they are all functioning as intended.This would only work from the map view and in areas revealed by the radar.