I've had a darn good stash with 20+ yrs of quilting but nothing near that !
I have some kits that are still on the shelf, and I remind myself of that when I'm tempted to buy a new one. I've given much of my older stash to our guild & bee for Linus quilts, to our elem school, church youth, Girl Scouts etc ... Maybe doing that would help you to clear out fabrics & patterns you won't ever use. I know that it really helped me to "clean house" and to focus on fabrics & patterns I still like and will use. When there's too much stash, it just becomes overwhelming both physically and mentally ...
Sounds like you could have some great sales here, no doubt you'd have some eager buyers ! :)