Here's my take on which flag goes where. They've been changing it a bit over the last few months so please don't take this for certain.
- Closure / Duplicate → close vote review queue
- Spam / Offensive → ♦ moderator queue
- Very Low Quality → ♦ moderator queue, moderator queue, low quality review queue
- Not an Answer → ♦ moderator queue, moderator queue
- Other → ♦ moderator queue
Some explanation:
- The items in the low quality review queue are determined automatically based on some heuristics, plus low quality flags by users.
- The ♦ moderator queue is exclusive to elected moderators and Stack Exchange employees. The moderator queue is accessible to users with ≥ 10k reputation. It allows 10k users to agree or disagree with existing flags.
Note that "very low quality" really should only be used for posts that are unsalvageable due to broken formatting, garbage content, et cetera. Meaning, they should be deleted right away. Questions that appear low quality most likely fall under some close reason, so please use that instead. Often they will just be unclear what you're asking. Closing questions is something the community can handle on its own—no moderator needed to intervene.