Maybe it is time to take those unloved, unused lenses out of the bag and give them a chance to show you what they can do. You can even post your results on the "
Lonely Lens Club" thread!
Your macro lens would be a good start. The challenges of lighting and composition when the subject is small should be a good creative stimulus. I own the Sigma 50/2.8 Macro. It is a good tool. You don't have to be working at the near extreme of its focus range. Try taking pictures of everyday objects but from a closer/tighter perspective than you normally would.
As for your 50-200...I have much the same problem. I seldom shoot at focal lengths longer than my 85mm. I simply don't look at the world through telephoto eyes. I even have a difficulties as times with the 85mm in that I forget the difference in perspective with even a short tele. So the assignment might be to spend some time at the zoo using your long zoom for its intended purpose.
With any luck, you will be able to get some great images, widen your photographic talents, and get your money's worth from the lenses you own rather than selling below value on the used market.
Steve