Yes, those are not products, those are vendors. The more I thought about the second part of this article, the more I realized I couldn't condense the tools from these vendors into a simple list. These vendors make some many utilities, things I feel are often must haves, I just have to recommend them as vendors. If they put something out, consider it; it might be obvious, immediately, how it will fit in or improve your workflow, or it might not... but its likely to be something intriguing.
I'm going to name a few products for each vendor here and try to give you an idea why I think they are essential and when I can some idea of how I use them.
Let's start with DimensionTheory.
I literally use this product with every render that includes a human figure: Project EYEray, Not only are the materials and textures excellent, it's also a merchant resource. I sometimes use these straight out of the box, they are that good. Usually I will apply some small adaptations to the cornea, but that's about it.
Tonal Rage is something that I would use in every render if I didn't mostly do my own tone mapping in post. I still use it for simpler shots and for help developing the final look of a piece. This really ought to be one of your tools, tone mapping is a hugely under-used but vital part of this render engine (wether in render or in post).
iRadiance - Light Probe HDR Lighting for iRay, there are 3 of these sets and I have and use them all. Not going to name names, but these are far superior to similar products (there aren't many). They do make for some interesting/challenging issues if you are doing your own tone mapping in post, but for all intents and purposes these are stellar light probes that can serve for lighting in virtually any situation. And as a bonus, they come in direct light and soft light versions, the soft light versions making it easier for you to embellish with your own primary light sources. I find myself turning to these sets more and more often these days.
Subsurface Workshop, I put this right up there with Mec4D's PBR materials (she just missed appearing on this list, between the materials and Unshaven) as totally essential. Fabrics, plastics, wax, hair.... there's a material in here somewhere that will breathe that extra bit of life into your render. I use the subsurface only materials on virtually every pieces of cloth.
Moving on to Zev0
Where do I even begin with this guy? His shaping morphs and fit morphs have been such an integral part of my workflow, for so long now, I frankly don't know what I would do without them. And when you add into that equation: the vascularity morphs, the automated bend control morphs and now the merchant resource textures/shapes for everyone from kids to old folks (I haven't created a character for re-sale, yet, but Fuller and Red would not exist without this: Growing Up Skin Merchant Resource for Genesis 3 Males and though this vendor didn't make the list, this product: Extreme Closeup: Freckles for Genesis 3 Males). This is a vendor who's catalog you ought to be shopping.
And that leads us very naturally to Zev0's frequent partner in crime: draagonstorm, the queen (I'm pretty sure on the gender here) of useful and innovative utilities. I have to start with Color Picker, a fantastic tool that lets you get the exact color you want from "elsewhere". I use it most often to pick a transmitted color for SSS from the actual texture maps of a character I am working on, but I've used it for easily a hundred other things, fine tuning colors. Skin Builder is something that I really ought to use more than I do, but the one time I really put it to the test it made me extremely happy and another brilliant collaboration between draagonstorm and Zev0 is Brow Remover, for those moments when you really love a texture but just can't stand the brows that come with it. And of course, once you have those brows gone... you really should add some new ones, and that's where Wow Brow comes in providing you with a selection of different brow shapes and colors to add on.
I know I just threw a lot of stuff at you with this article, this is not my usual style. If you'd like more information or usage tips on anything mentioned here, please feel free to comment below or in any of the places you find this article posted.