Would be great if we could set filters on our inventory slots so that only specific items can go into them. An example of how this would work. You right click an empty slot, select Iron Rod from the item selection. The Iron Rod shows up in the slot, with a lighter color indicating that the filter has been set. Only Iron Rods can go into this slot, and this slot fills up first. To clear a filter, right click filtered slot (that is empty of items) and select "Reset". This would be amazing if it was implemented not only for the player slots, but also for the vehicles, vehicle stations, et. al.