I am a scrappy girl thru and thru. I could never do a 2-3 fabric quilt. I shudder at the thought.
My first scrappy was a log cabin and I had to pay attention to light, medium. and dark values so much that I forgot to worry about if a color went together. Even today I will see two colors that I can't abide next to each other and I have to change, but I found out, even if I change it I will invariably put these two colors together anyway, somehow. So, I really don't worry about it. I just finished a spool quilt (Bonnie Hunter's leader/ender challenge for last year.) I made over 1,000 3 1/2" spool blocks and everyone was different. It's on my long arm now and I love it. Bonnie just finished her mystery quilt and what I like about her patterns is the controlled scrappiness of them. I didn't use her color palette but chose my own and used bunches of different fabric within that color palette. Give yourself a chance to create your own special scrappy style.
I do respectfully disagree with the poster who said scrappy was not intended to be and shouldn't be kitchen sink. That is exactly what scrappy started from. The farm wives used feed sacks, old clothes, and such, anything they had handy. We are lucky enough we can be a bit more selective now. I also disagree about using only certain "styles" of fabric. I don't have many of the more modern styles, but everything I have, if it's in the color range I'm looking for in it goes. I sprinkle batiks in with the civil wars, with the 30', anything goes in fabric choice. Bonnie Hunter says about ugly fabric. "If it's still ugly you haven't cut it small enough". She is so right. So, think twice before not using what you think of as ugly. The ugliest fabric I've ever owned (don't know where it came from) was on the cover of a book. I laughed so hard at that.
What have you got to lose? Give yourself permission to really go crazy and mix like mad. If you don't like it, donate it, someone will love it.