Image Editors
If you need to resize or do some basic image editing then check out resizeimage.net .
If you need something a bit more advanced then you can use Pixlr or GIMP which are excellent free photo editing applications.
File Transfers
Depending on your email provider, it might not always be possible to send the files you want to somebody due to the file sizes involved. Wetransfer solves that. The free version allows you to end up to 2GB to whoever you want.
We use 7-zip to zip / extract our files which you need to do before sending them.
Stock Photos
There are many many sources of both paid and free stock photos available online. Below are just a few that we use regularly.
FREE:
PAID:
Free Fonts
Google fonts have a wide variety of fonts to chose from which we'd recommend in using on a lot of our projects. They are free to use and easy to link.
1001 free fonts have hundreds and hundreds of free to use fonts. Just keep an eye on attribution.
Colour schemes
There are many many tools you can use for free in order to get a colour scheme for your project. We like to use Coolors to generate from scratch or if you want to make a custom colour scheme from a particular picture, then we use Pictaculous.
For a better understanding of colour theory, Paletton and Kuler have nice tools where you can mess around and see the different variations of a scheme.