I've found cheap skate shoes to be super beneficial for me. A wide heel platform and tough construction save my feet wear and tear.
My buddy races downhill, and when he gets new body armor, gives me his old stuff. It reeks, but one trip down the rio and it's all the washing I need. Shin pads with knee go on everyday and elbow pads in anything II+.
As far as leashes go, I've been making my own. Ordering a coil leash keeps it off the board and less of a snag hazard trailing behind you in the water. I remove the ankle/knee cuff and put on a rail saver, so I have one at both ends. That goes to a stainless steel ring, that slides of my QR belt easier.