Idk if this will be fully relevant to game art, but I’ll share what I normally do for art, more with a focus on references. My program of choice is Krita. Others have already brought up some good programs and resources

For Reference Poses and Images

• same.energy lets you search for a picture and displays what it thinks are similar images.
• PoseManiacs is a site that has a bunch of pre-posed 3D models in all sorts of poses that can be handy for getting down a specific gesture. With 3D models, I wouldn’t really try to closely reference muscle shapes and such, since deforming a 3D model usually isn’t accurate to a real human.
• If you’re on Windows, I’ve used Design Doll in the past for, again, basic posing, like Pose Maniacs. It lets you customize and pose a humanoid mannequin
  • For Linux, I typically just use Blender with the MMD_tools addon to pose MMD models (usually from Genshin or HSR since they give those out for free) and work from there.
• SketchDaily is a site that will show you a set of images for a short amount of time with the idea that you try to draw the overall gesture of the image. It’s a training tool for quick gesture drawing, which helps improve your overall confidence and ability to look at a reference and parse out whats most important.

and another thing, idk if you have a good eye for telling AI generated images from real ones, but I’d say try to avoid using AI as reference, since AI stuff can be inaccurate to real life, in both subtle, and not so subtle ways that could cause you some frustration down the line when learning. There have been times that I’ve sat down to do a study and got a bit into it before realizing it makes no sense compared to what I already knew and the image turned out to be AI Generated. Pinterest can have a lot of nice reference images too, but it really has become overrun with AI slop.

Try this one. LibreSprite

here is a tutorial for how to use it

I use Aseprite but that’s $20.

Well, it may depends on the style you’re going for.

If this is pixel art, which i found relatively easy when having no big artistic background, i can recommend those youtube channels : AdamCYounis, Brandon James Greer, and Pixel Pete. I also hugely recommend the series of mini-tutorial over here, it’s pixel art tutorial all in pixel art, and it’s amazing.

If you’re looking for other styles, i don’t have ressources to learn. People already recommended Gimp and Inkscape (and Blender, you can do a bit of 2D in there as well, though it may not be the most comfortable way). I’d also add Krita, which is more meant for traditional drawing. It works way better with a graphics tablet though, but even a cheap one does the trick.

So, there are many answers to your question and it all depends on what you are looking to do.

Speaking in term is FOSS (free and open source software) Inkscape is a great vector program, Gimp is a great raster program and Blender is an amazing 3d one. (I know you said 2d but adding it in just in case)

If you are looking to make simple images then you might want to start with gimp. If it’s specifically pixel style art there are plenty of tutorials online. (https://thegimptutorials.com/how-to-make-pixel-art/)

If you are looking to make clean line art then you will want Inkscape. Think close up perfect circle with no squares or pixels. There are plenty of tutorials for this program as well.

Now, as you grow and learn you will find and learn about other programs that do the same things. Keep them in mind because they may work better for your needs but for the short time you start keep on the path of these two. They are the most know free options there are and will have the most resources to learn from.

https://orama-interactive.itch.io/pixelorama

This software is free and I’ve seen people get some amazing results out of it.