I was looking for one sometime ago... So after bunch of research and asking all over place I came up with the following list I want to share:
Fenwick Bamboo Pad: Browsing Store - Fenwick Bamboo Saddle Pad Liked it a lot: Soft, BIG (that's crucial for my 18" size saddle :) ), easy to wash/clean, and non-slip indeed. I got the grey color one - love it (much nicer than black). The only "downside" - it may look/feel "puffy" until you put a saddle on top of it.
Ecogold Pad: https://www.ecogold.ca/product_info....0j2qb116hejce5 Let me first say I was talked into it 3 years ago by my, then, trainer, who claimed it'll help me to stay more balanced and will be easier on horse's back. Neither was true (I was as bouncy as it comes and ended up getting Thinline contour pad anyway to protect my horse's back). It IS a nice pad (and their Customer Service is very nice), but price is just way too high. I have A/P version I use with my jumping saddle, but I'd never spend those money if I'd look for one now.
Success Pad: Success Equestrian Deluxe Dressage No-Slip Saddle Pad - Quality Tack at Outlet Prices - VTO Saddlery It looks very similar to Ecogold. I got mine for half-price and I'm not NOT going to buy another one. Their "standard" size (the only one they had that time) is tiny, my saddle barely fits in. And (the worst) when the horse sweats the upper part becomes sticky and yes, sticks to everything above really badly - whether it's Thinline pad or a saddle. After riding in it once on warm day I have white dots on my Thinline pad I wasn't able to clean off. :(
Barnsby Pad: World Champion Horse Equipment - Horse Supplies and Horse Tack (and SmartPack also carries it, but only in white). People swear by it, but I never tried one (and it's on expensive side).