A fighter set or something to cover lack of usefulness of Fighter sets, as aggro is completely useless in single player. There are rogue sets and such but they don't really vibe well with a shield 1handed fighter style if you're into that kind of thing ( as keeping real to a class style and not mix and match to make it work ).
For example, ladybug set is great for a tank build, but half of it is useless in single player so it feels like you're lacking. Currently that style of play is being forced into a rogue set most likely, to be more relevant.
Note: this is single player oriented suggestion. In multiplayer Fighter sets are amazing, full ladybug + ladybug shield makes you into an immortal tank in essence, with mutations on top.