I have no wall, but I have more than enough. But of course I don’t use everything in every piece of music I make, and of course I don’t want to sell all the stuff that wasn’t used in the last thing I made or even in the last months.
It’s like spices on your shelf. Hopefully you don’t use every ingredient in every meal, but sometimes you reach for something and it’s really, really nice if it’s there to use.
I like my modular to be able to support any (or almost any) crazy experiment I will think of in the future.
Back on OP topic: No easy solution I know of but a few things that helped me:
- Making my sounds more “dynamic” or “changeable”. Modulation and hands-on helps me a lot.
- It’s easy to fall into the trap of slapping yet another sound or thing on the music, when in facts the problem is either that the sounds I have going are not saying enough or the whole composition or the idea behind it, is actually unclear or just really poor. I try to get better at killing my darlings earlier in the process, which helps in this regard.
I have no idea if this helps 
EDIT: All the above might come across as know-it-all, which couldn’t be further from the truth. I try to learn all the time. Sometimes I throw too much on a track, sometimes too little, and every once in a rare while, I like to think I, by a stroke of luck, got it just right.