There are Decorations (Utility) that you can get that give gathering skill items when you use them. I have a small Slicing one that gives me small lockboxes, but I was wondering if there was one that gives lock boxes with more credits in them. And, if so, which one should I get for the biggest lock boxes?
That would be the Encrypted Terminal, which gives the equivalent of Makeb's slicing nodes' lockboxes (level 51-55 or Grade 9). Grade 11 nodes (Rishi/Yavin) have not been added as decorations yet.
Do note that this is an absolutely terrible way to farm credits ... a half hour spent slicing on Yavin will net you more than exhausting the decoration node on all your characters.