sites/software i use:

1 | Photoshop CS6

Pretty self explanatory. I use it for literally everything. Recommend it to everyone.
*yes you can find it for free*

2 | DeviantArt

Where would I be without this site... Amazing resources. Pngs, photopacks, textures, fonts, stock, PSDs...
There is some weird shit on here but as long as you stay in your lane you're fine.

3 | Pinterest

I think everyone uses Pinterest tbh. Great for inspiration. I used to only use Pinterest to find pictures for covers, but I'm using it less now because the quality is not always good.

4 | Pexels

I used to think stock images are ugly. I was a fool. 

5 | Coolors

Best source for color palettes. You can generate them on the spot, alter them, save them, download, or browse other people's palettes. There are also gradients, but i don't use them. 

6 | Tumblr

Great for gifs. 

7 | Dafont

Great resource for fonts. 

More about fonts in next chapters.

apps/sites i don't use but a lot of people do:

picsart (for editing)

ibispaint x (for editing) 

phonto (for fonts)

polarr (filters)

photopea (website similar to photoshop)