Rawpixel:
Aside from creating my own designs, I love to search out designs that are available through Creative Commons/Public Domain, and then re-imagine those designs and put my own twist on them. Rawpixel is a great resource. A word of warning; it can become a bit of a ‘rabbit hole’ once you start searching!
Old Book Illustrations:
The title is pretty self-explanatory… this site has a ton of great Public Domain illustrations from old books. Another ‘rabbit hole’ adventure! Old Book Illustrations has some pretty amazing illustrations that are free to use, however you may need to spend time doing some digital clean up before you use them.
Rijksmuseum:
Rijksmuseum is another great site for finding prints that have recently been released to the Public Domain. They also offer some great tips on how to use the designs and prints!
PDF Escape:
PDF Escape is a free online resource for modifying PDF’s. This is the programme that I use to add text boxes to journal pages, etc. to allow them to be ‘fillable’ once you download them.
paint.net
This is another free programme, however you do need to download it to use it. This programme is great for removing backgrounds on images to create a PNG. As well there is a option to resize your image. So if you download something in a low resolution/DPI you can increase it to a higher quality through paint.net with just a couple of clicks.
Lunapic:
Lunapic is another free site for removing backgrounds in images. It also has a pretty great stash of editing options available to use!