So after browsing on Gelbooru, Google, and Deviantart, I came to a conclusion. If I use those sites, I just can't seem to find enough to work with.
SO. If there are other sites you all know of where I can find decent pictures, Please, let me know.

Also: I say this because I've been browsing for almost 5 Hours and have yet to find a usable picture.

Zerochan? Danbooru?

In my past experience, in general, Pixiv contains a good 90% of existent hentai on just about any character from any source that is Asian (Japanese, Korean, etc.) in origin. If it's not there, you can sometimes find a few others discovered on artist websites/twitters/tumblrs posted on Gelbooru and the like. If you're really lucky, you might find something that you're looking for over at Hentai Foundary, but that's not all too likely, really.

Also in my past experience, if none of those places have what it is you're looking for, then it probably doesn't exist. I know that I'm pretty much always limited to things I can find on those sites despite searching every source I know.

A while ago I started a thread where people could share images in their manip folders: hypnohub.net/forum/show/6262

If you want I could share my manip folder with you. Although, I had a different style of manipping than you, you might be able use some of those images.

e621 has some stuff, though it's mostly furry stuff. There are also "rule 34" sites...but they're plagued with pop-ups and god only knows what else.

For the most part, you're going to want to just wander around the internet. Eventually you'll stumble across something that clicks.

Hope it helps.

You could also check the Booru "Root Database network": booru.org/top

They have the list of all currently running Booru's - Ours Labelled "Hypnobooru" (Also the name of our old booru before we moved, Vanndril correct me if I'm Wrong)

You should find something specific your looking for, since most booru's are themed; I.E the "Realbooru" - an imageboard of real life photos.

Finding really good images to work from can be one of the hardest parts of manipping. I find there are plenty of great images out there, just not always ones that will translate well to a hypno image.

You shouldn't be having too much trouble finding decent pictures on gelbooru... are you just browsing randomly or are you taking advantage of tags for your searches? I use tags all the time to filter my searches, not just for looking for a character/artist/show but also for specific poses or accessories that would compliment a hypno manip (like headphones or a monitor).

You're right.

But the entry for hypnobooru and the information therein are actually for the original booru from before we moved. Our current statistics don't update and display on that list. Just so happens that hypno.booru.org redirects to hypnohub.net, now, thanks to Slayer.

If you can't find any good pics on the whole of Gelbooru and Danbooru, you're never going to find any.