Most freelance designers use an impressive number of tools and resources in their daily and weekly lives. After all, they have to deal with the design and development as well as all of the aspects of running a business. The post is broken down into two major sections, business resources and design/development resources, and tons of smaller sections. I hope it can be helpful for you. Of course, this is not by any means an all-inclusive list
Patricons
Be one of the first people on the planet to download and use these clean icons for one of your projects. Sliced and ready for use straight after download, as they are transparent you can use them on any background you’d like. Set is of 24 icons in 32x32px size.
Blaubarry UI Kit
Check out this slick (and free) UI Kit from Design Kindle
Blaubarry UI Kit is a PSD full of useful buttons, sliders, scrollbars, and form elements. The file makes use of shape layers for easy editing and resizing.
Google Icons
Great mini-collection of Google icons by Sebastian Hager
Download them here