JLPT N3 is the midway point between basic japanese and proficiency. Unlike N4 and N5 you will actually start to see more “real japanese” in the JLPT N3 test and not just class room japanese. This is the level where you almost will be able survive most everyday situations, far from fluent or even proficient but definitely good enough to call it a merit.
With that said, there is one notable difference between study prep materials for JLPT N3 in comparsion to the lower levels, n5 and n4. In the case of N5 and N4, working through standard textbooks like genki or minna no nihongo is all you really need to pass with a high mark.
However at JLPT N3 it’s start to look a little bit different. You can definitely pass N3 by just going through standard textbooks like tobira or AIAIJ but the prep books come in real handy for filling holes in your vocabularly, grammar… etc.
My personal favorite is sou matome series. Easy to understand and if you work through all vocab and kanji you shouldn’t run into an unfamiliar word or kanji on the test. However, not a fan of the sou matome grammar book. That’s my only grip with the series. The kanzen master grammar and TRY! JLPT N3 book is superior. My ideal combination is sou matome vocab+kanji books and TRY! N3(for listening and grammar repetition). I didn’t use kanzen master but I did skim through it and I liked the layout and explainations far better than I liked sou matome. The sou matome grammar book was very light on explanations and examples. I could see why some people like it but it felt like I wasn’t actually learning anything.
As for standard textbooks, tobira or AJAIJ is fine. As always, the standard textbooks should be your main way of learning japanese and only use the prep books as a supplement and repetition weeks before the test.
Although grammar dictionaries aren’t necessary but they can be useful. I recommend the dictionary grammar series but you definitely don’t need the advanced book. The basic and intermediate will do fine.