As a game developer hobyist, one of the main concerns is getting resources for my games. I have shared some of my findings on my blog, but here is the list of extra ordinary findings, if you are looking for free or affordable art for your games.
Resources for Affordable Graphical Asset
2dgameartguru.com is one of the most interesting resources that provides not only free and affordable art, but also attempts to teach you to edit and create your own art to fit your needs, with a moto "Life is too short to make bad art". Best resource for developers learning to create their own art. Site is managed by Chris Hildenbrand an awesome designer with lots of experience and a great graphical style. I just love those characters he makes.
Graphic Buffet is my first stop when I'm looking for a theme for my game. Has tons of affordable resources and lots of sales throughout the year (Including amazing sale now, everything down to 5$, don't miss it). The store is managed by Ian Garstang, 2d art specialist, and with his cartoonish style, you just can't make a bad game.
GameArtGuppy is also one of my top choices. It has lots of free resources, and paid ones have really low prices. Managed by Vicki Wenderlich, with her awesome cartoonish style, you can see and recognize her graphics in many small Indie dev published games.
Kenney.nl is one of the no brainer must haves. For a small donation (or big one, if you can afford it) you will get tons of free graphics and lifetime updates, any time they add something new. Kenney foundation really made a difference in Indie game industry, and I wish them all the luck with their Kenney Land project.
Of course we can't have this list without OpenGameArt, the biggest catalog of free game art available out there. It might take some time to adjust to find what you want, but in most of the times it will be worth it. But if you are into pixel art, then OpenGameArt will be like a paradise for you. Also have sounds and other assets too. The resource is managed by Bart Kelsey and if you like this awesome resource, don't forget to support it on Patreon.
Another interesting resource is Daniel's Cook's LostGarden, which not only provides free game assets, but also lots of insights game development, and some time ago Dan even made a little game hackathons to create some game with some goals from provided graphics and make them as fun as possible.
One of the new founds I have not yet explored completely is UnluckyStudio. Which provides not only great free game assets, but also share their experience on game development.
Next there are couple of game asset markets, where you can not only get free or affordable graphics, but also sell your own, if you have what to sell.
GameDevMarket - is a marketplace for high quality, affordable game assets handcrafted by talented creators around the world.
GameArtPartners - One of the largest markets I saw out there.
SuperGameAssets - Not an open market (you can't sell your graphics), but is a very good resource to check when you are looking for affordable graphics
This is a new addition, I just recently found: MobileGameGraphis. But could be easily to list of my favourites. Ran by a team of game developers and graphical designers, they provide full packs with almost everything you need to complete your game under specific theme. One additional great thing they have, that they extend their packs with new additions, if the graphic pack is popular enough to get the needed amount of social shares - called Milestone Rewards. Definitely check them out if you are searching for graphics for your game or need to find a theme for inspiration.
Game-Icons.net seems to be one stop resource for vectorized icon graphics, if you need anything for your UI elements or even finding something for your game icon.
I myself do not use Unity, but suggested here, that Unity has an excellent assets store which also include even free graphics. And after checking it out, indeed, while there are lots of assets provided in some Unity bundle format, you can also find some hidden gems there too.
Another suggested resource is Reiner's Tilesets. While website is in German, you don't need to speak German, you don't need to understand German to be able to find 2d or 3d tileset elements or textures to download. And this website has plenty of them. (And now I found that you can switch language too :) )
Yep, still keep updating and adding new great places to get free or cheap art from :)
Craftpix.net has a new and interesting approach. They offer membership for monthly fee, that gets you access to all the assets and unlimited downloads. New assets are added on the monthly basis. And you can browse and see all the collection they have already. From full game kits to UI elements and icons. This is truly all you can eat buffet for a monthly price :)
I am not using Contruct game development tool myself, but it is worth to mention that they also have a separate Scirra store where you can get graphics, music, sounds and much more, not only compatible for Construct, but for other engines too.
OpenGameGraphics has a lot of free game art. And they even offer a promotion: Subscribe to their new letter and get a Free premium character right now.
Hope you can benefit from the list as much as I do when working on my games :)