We've had many discussions over the years about original series wackys that are difficult to find in high grade. Sometimes it's because of inherent centering issues, sometimes the reasons aren't as obvious.
Rather than mentioning some of the best known stickers in this category, I'll start with the Bum Choke 4th puzzle. After ten years, I have exactly one piece that's in true NM/M condition without any wax.
As far as stickers, I'll start with 2nd series 8-Lives and 3rd series Sweathard (both always off center) and let others add to the list....
Here are a few from my experience:
1st - Kook aid
2nd - 8 lives, awful bits, gyppy pop ditch masters
3rd - raw leaves, sweat hard, moon shine crackers, windchester
4th - blue beanie, gatoraid, land o quakes
5th - tijuana smells, shot wheels
6th - play dumb, clammy, bum bums
7th - big muc, contrac, creature crackers
9th - Pigpen oil, GI toe, Jerky fruits
10th - tic toc, caraid
11th - gulp, fib, bash, alpain
12th - battlecaps
13th - doomed, sneezer
14th - Aint, sell'em
15th - fang edwards, bandage
This list varies mostly they are hard to find centered. A few are notorious diamond cut or misshaped cuts. And another few just NEVER seem to show up in nice condition no matter how many lots I look thru.