Ebay has "Long Board Sandpaper" in either rolls or pre-cut strips- - - - -around 500 listings. There's plain back, self-stick, and hook and loop types. I used to use 40 grit for roughing out filler and 80 to 320 grit for progressively smoother finish work.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!