I've found the ignore list to be very useful. For example:
In the SRV, ignoring maxed materials mean they go to the bottom of the contacts list so you can simply mash the select key to pick up the materials you do want on high G worlds.
In a wing, I can ignore specific materials that other wing mates want and let my limpits collect the rest.
Mining, you can select specific elements to ignore, so fragments with multiple elements will be captured and processed, bu the ignored elements will be dumped automatically.
The fact there's no specific ignore list manager doesn't appear to be issue, as the items still appear in contacts at the bottom of the list, which is where you spend half your time when collecting materials anyway. Also, if you manually select an ignored item when in an SRV you can still scoop it, which is useful for mats list Iron, Phosperous etc that you occasionally dip into to refuel, repair, rearm etc.
The only annoying feature is the requirement to now select items for collection twice due to the additional ignore submenu. This is however only an issue in the SRV where there are other Outcrops etc around, meaning you have to scroll down after each collection to select the next material for collection. If you're mashing the select button and then hitting down, it's very easy to ignore instead of select for collection. This is however only an issue on high G worlds, where you can "speed mash collect".
