You might want to return to Darkmoor and farm the plant boss for the
Law of Kan Davasi Band. I personally think it's much better than the A&O Ring and still use it as part of my endgame gear.
Polaris doesn't offer too much for a gear upgrade. I would mention the shoes from the Rat but your pack shoes are most likely better. You could farm him for
Yolok's Ampul of Observation if you want to sacrifice your Mythblade Item Cards for more defense, but this is probably not a great idea.
Other than that, you can farm Omen for a deck upgrade.
Luphilim's Legend Cards offers you better stats than the Darkmoor deck, though you will start to see the maximum copies stat diminish. Shouldn't be an issue in PVE.
Mirage also is pretty sparse on gear. If the
Time Warden Galesh of Reason is better than your pack boots, then go ahead and grab them from Shadowbones. If you want to sacrifice pip chance for a more damaging ring, you may wanna farm the Verboten Mimic for the
Drake Ancestral Signet.
Things get spicier once you're in Empyrea. You'll most likely wanna swap out your robe for the
Quixotic Light Brigade Armor]Quixotic Light Brigade Armor from Corporal Tenni'syn. Almost everyone in the first half (pre-Medulla) will drop a glass cannon
hat and
boots. Once you're in the second half, feel free to farm the various bosses in the Husk for more new gear. Such as
this deck from the Arachna Magna Magus, yet another
hat and
boots from the Luphilim boss there, and a
ring from another by-then familiar face.
And then it's onto the Catacombs. Most people just farm King Detritus to craft all the gear that they want from there. You can buy all the recipes from
Zasha EmberForge You'll want the Dragoon hat, boots, and amulet. Depending on your playstyle you may also want to get the athame or ring.
Karamelle's gear is pretty much just a slight variant on Dragoon gear. You may or may not find it useful, and if you do it'll be pieces like the Athame or whatever.
There's one gear slot that isn't really worth farming for in any of these worlds, and that's the wand. If you or a friend has the Sinbad Gauntlet, farm it for the
Kapudan's Grappling Hook. Unfortunately there aren't very many good free-to-play wands at this stage of the game, but if you can't get the Sinbad wand I guess you could just use the
Baba Yaga's Focused Mace that you can craft in the Arcanum.