Have you ever tried extension tubes? Kenko makes a set that is compatible with Nikon bodies--they tend to be used more for macro than a teleconverter. Manual focus is better suited for macro. Can you use Live View on your body? I've found using LV and manually focusing gives me better results. Good luck and have fun!
I macro every which way
Kenko extension tubes - check
Magnifying filters - check
Macro (aka Nikon-speak Micro) lenses - check and check (60mm AFS and 105mm AFD)
And that macro light gizmo pictured with my latest addition the Kenko 2x T.C.
I've also played around with DIY macro light benders.
I have also used the Kenko 1.4 TC with my macro lenses.
I have a longer lens macro on my lens lust list - like the Sigma 180 - at about two grand CDN $
And I've looked longingly at the Laowa 15mm f4 Wide Angle 1:1 Macro (under $700 CDN$).
I also have fun taking shots of bugs with telephoto lenses - hard to nail it from 10 feet away with the 200-500mm lens but nice when you get it.