Ahh..the ancient challenge of inspiration
Yeah, I agree with you frolf. Yes, flowers are pretty and bugs are fascinating..but how many are them really are wall-hangers?
I enjoy macro photography and I deliberately try to avoid flowers and bugs, largely because I find them ultimately a little "repetitive" in a way.
What has helped me stay interested is to try and think more abstractly about materials, light and textures. Macro photos doesn't have to have recognizable elements...the viewer doesn't have to know "what it is", but simply enjoy what is beautiful.
Different colored lights and metal mesh, a vibrating surface of mercury with a couple of LEDs giving both highlights and casting shadows, prisms sunk into colored liquid and some powerful lights, beautiful glossy lips...whatever would look interesting and/or beautiful if you were 1/10 of an inch tall