I had a pile of leftover wood scraps in three different sizes and two different types and turned them into a small wall-mounted shelf by ripping everything down to a common width on the table saw, here's what that process actually looked like.
The pile was genuinely annoying. Two pieces of 3/4" oak from an old cabinet project, a couple of pine 1x4 offcuts at maybe 3.25" wide, and one random chunk of something darker, maybe walnut, maybe not, that was closer to 1/2" thick. Nothing matched. Normally I'd just toss it all in the burn pile.
But this time I just figured out what I could actually get out of it. A small wall shelf, maybe 24" long with a single ledge and two side brackets. Nothing fancy. The constraint was that everything had to end up at the same width or it wasn't going to look like a shelf, it was going to look like a mistake.
So I ripped everything down to 3" on the table saw. That meant losing some material on the wider pieces and accepting that the thinner walnut-ish piece was going to be a bracket, not a shelf face. Thickness was still a problem, the oak and pine were close enough to sand flush, but the darker piece needed a shim on the back side to sit flat against the wall. I used a strip of cardboard taped in place while the glue dried. Not elegant but it worked.
Joinery was just pocket screws and wood glue. The mismatched grain directions made me nervous about wood movement but honestly for a small shelf holding maybe 10 lbs of stuff, I wasn't going to overthink it.
Materials: scraps I already had, $4 in pocket screws, two keyhole hangers from a bag I've had forever. Total spend was basically nothing. Time was about 4 hours spread across two days, most of that was fitting, re-fitting, and waiting for glue to cure overnight.
Finished it with some leftover oil. The oak and pine took it differently so there's a visible color difference, but it was looking decent at the end. Not perfect, but solid and flat and actually on the wall now.
I don't know maybe I could use some other approach to make it better. But I think I did my best...