Creative content such as lives in three realms of intellectual property rights protection.

• Copyright (All Rights Reserved) is a form of intellectual property, applicable to certain forms of creative work.  It is a legal right created by the law of a country that grants the creator of an original work exclusive rights for its use and distribution.  These rights frequently include reproduction, control over derivative works, distribution, public performance, and "moral rights" such as attribution.  https://en.wikipedia.org/wiki/Copyright

• Public Domain works are those whose exclusive intellectual property rights have expired,^[2] have been forfeited,^[3] or are inapplicable.^{[4] https://en.wikipedia.org/wiki/Public_domain}

• Creative Commons (Some Rights Reserved) Copyright gives creators exclusion rights to their work, but with today's technology, users often want to reuse creative content. Historically, to do this, a user would need to contact the creator and ask for permission to use the work. Today, we have a new method for reusing creative content through the use of Creative Commons licenses.

3D Models

• https://thenounproject.com/ -  a resource of icons

Building a Global Visual Language from Noun Project on Vimeo.

• http://www.freepik.com/ - Freepik offers users, high quality graphic designs: exclusive illustrations and graphic resources carefully selected by our design team in order to provide our users with great content that can be used in both personal and commercial projects.

• https://creativebooster.net/ - A resource of free fonts, mockups, and graphics

• https://www.fontsquirrel.com/ - 1000% free for commercial use fonts

• https://fonts.google.com/ - Making the web more beautiful, fast, and open through great typography

• https://unsplash.com/ - Free (do whatever you want) high-resolution photos

• https://www.flickr.com/search/?license=2%2C3%2C4%2C5%2C6%2C9&advanced=1&text= - On Flickr, you can find images that allow you to reuse, modify, and commercially use depending on the rights associated with an image. Be sure to check the individual image rights.