What kind of software exists that can aid in finding/creating reference material for traditional drawings? I know of blender, are there any with lower entry level skill requirements?
The best software you can get comes preinstalled in the Frontal and Occipital lobes and Wernike’s area. They may require the nature, library and search-engine plugins, but that should be all you need.
Sorry, if I an sounding a little glib, but no software is going to do it as much as an inquisitive mind.
Are you looking to make Maquettes?
I believe it is still free for web use and it’s very limited in the number of pre-loaded poses you can get (as in maybe 12) so you have to be able to visualize what you want, which requires some ‘drawing’ skill. You have to pay and download to get the full version and I believe it is only iOS or phone compatible. It does NOT work on an M1 or M2 Mac even though it said it did (I haven’t tried it in a while.)
Another one that is quite a bit more spendy and a slightly steeper learning curve is https://www.posersoftware.com/
It has quite a bit more detailed libraries available. Costs $$$ for additional libraries.
Let me try to understand what you need. Reference material to draw what?
Of course the first option is a google search. If you are drawing a tree google tree images.
You mention Blender. Blender will do nothing for you unless you have a model. You can put a bunch of rectangular boxes and a camera to play with as references for the perspective of a city. But if you want a reference for a teapot you need first the teapot and second you need to add materials light and framing. So Blender is probably not what you need unless you want to really exploit knowing and understanding it.
If what you want is references of objects one option is to play with sketchfab.com which has a lot of models where you can rotate to see different angles.
If what you need is references for posing people, the best option is Daz3d.com, which has some free models and poses you can use. You can pose the character in any way you want but you need to learn how to do it.
A pose is nothing without lighting, so if you have some Nvidia GPU you can generate good photorealistic renders with controlled light. If you do not have that GPU the render quality is inferior.
There are some assets you can buy (which I recommend) For example you can buy a skeleton model which you can pose, use that exact same pose with a normal model with muscle textures to understand the anatomy, use the same model and pose with normal skin, change the model with the same pose from female to male, or change how muscular, skinny or chubby the character is.
You can also export the models to Blender.
If you want anime-style people and an easier tool to use (Daz can be a bit complicated) use DesignDoll terawell.net It has no photorealistic render engine, so it is not to reference illumination, but is fun to use.
An alternative to Daz is Iclone but it is co$$tly. The advantage is that it has more options to customize your character with Character Creator. (But I prefer Daz)
And of course you can generate reference images using AI, like Midjourney, Sable diffusion, or Dall-E.
It still is a hit-and-miss. I would still recommend Daz as the best option to control the posing, lighting, and details.
I haven’t tried Daz. The Magic Poser I mentioned does let you control the lighting angle, which can be helpful.
I’m old enough to have quite a library of reference books that show poses from a lot of different angles. It’s probably quite an antique set of books now, LOL.
A word of caution, as always. If using photos from the web as traced references, that is usually not a good idea. Most photos will be copyrighted by their owner. Creating a derivative of their photo violates that copyright. Tread carefully.
DAZ used to be one of my freelance clients. I designed much of their marketing collateral for a couple of years.
One of their products is DAZ Studio. It’s a free application where hobbyists can take high-quality 3d models and manipulate them in various ways and poses, then dress them up in various costumes and environments, which are purchased as needed from DAZ.
It’s all very high-quality, but it’s sort of like a Barbie and Ken approach to 3D modeling, which might be exactly what the OP is looking for.