Amongst their 100+ site range,
http://www.liondollars.com/ have a few little diamonds in the obscure niche front.
Have a look at these:
http://www.fuckbuddyseeker.com goes straight to the heart of what online daters are REALLY after - GETTING LAID !!
http://www.asstomouthhumper.com gives an especially hardcore approach to the ATM niche.
http://www.bizarresextapes.com covers LOADS of B&D, Latex & Leather and other similar fetish niches.
http://www.dutchpeefest.com goes deep into European pissing and watersports.
http://www.gapersex.com well represents the "big hole" niche.
http://www.giantdicksuckers.com looks at the huge dick niche from the oral angle brilliantly !!
http://www.preggomilf.com twists the MILF/Mature and pregant niches into one.
And there are heaps more with awesome content, and with new sites weekly, they never get stale.
Over 10000 un-watermarked promo pics, in convenient sets all for zip download and over 20000 hosted galleries.
They literally have something for everyone !