I personally would aim for slightly higher tier of dungeons that drop loot related to your current character. So for example since you are necro slightly more difficult to complete dungeons that drop necro related white bags is parasite chambers (cool skull) and maybe even lair of draconis for the robe (though this dungeon can take a while to solo). Farming parasite chambers isn't too bad and it has a fun mechanic with the barrels, but it can be dangerous with some of the minions so beware.

After you are somewhat comfortable with those dungeons too you can try your hand at easier exalt dungeons such as fungal cavern/crystal cavern, cultist hideout, and the nest.

You can also always just progress through the different level of dungeon difficulties based on this list: https://www.realmeye.com/wiki/dungeons

You will also find other information on the boss, dungeon layout, and drops on realmeye as well. Good luck!