Manufactured mats - take a medium combat ship to a LOW RES in a gas giant ring system. I would use a Krait MkII or a combat-equipped Python I. Instead of loads of armour, fit the ship with 4E and 5E cargo racks and a 5A and 3A collector limpet controller. You can fine-tune this setup by varying the cargo space and/or required number of active limpets. Fly to the RES and attack any ship who scans you with an accompanying troll comment, like 'What do you have in your cargo hold?' or 'I see all!'. Wipe them out with extreme prejudice. Collect the debris from these idiots and there's your mats.
The reason for selcting a LOW RES is that you will get easy kills, from foes who are no more dangerous than your local ice-cream man - hence the reason why you can spare ship space for cargo and collector limpet controllers instead of armour.
Also, I do this only in Solo play. Makes it much less complicated, and the only trolls will be the NPCs you're about to kill.
Data and Raw mats - Find a system where there are pirate-killing missions that are set in your gas giant system, which will be fairly close as generally only local systems care about what their neighbours are up to. Stack** a few missions from different providers where part of the reward is Raw or Data mats - look for the little Engineering hexagon symbol in the mission tags. Fly the missions at your friendly gas giant LOW RES, collect the Manufactured mats as you fight; return to the mission providers and collect your Data and Raw mats as part of your mission rewards.
This is a great way to gather mats, because you get to kill all those insolent trolls who have nothing better to do than to peer uninvited into your cargo hold. Death is simply too good for them. Of course, you can always scoop up the damaged escape pods, leaving the occupied ones containing the trolls to suffocate slowly....

** Stacking missions means accepting missions from different providers, but who want you to kill pirates from the same faction. So, you might accept missions from [fictitious factions] Colonia Coppers, Jaques Friends, and Ratraii Rescue Rangers, who all want you to kill Brian's Thugs pirates. One kill of any Brian's Thugs ship will count as a kill for each of those providers at the same time, so you are effectively completing three missions in parallel.