https://validately.com/

https://www.applause.com/

https://www.usertesting.com/

https://www.trymyui.com/

http://openvoyce.com

https://usabilla.com

http://betatesters.io/

https://www.pickfu.com/pricing#poll

Creating Usability with Motion: The UX in Motion Manifesto
https://medium.com/@ux_in_motion/creating-usability-with-motion-the-ux-in-motion-manifesto-a87a4584dd

Getting started with UI motion design
https://medium.com/this-also/getting-started-with-ui-motion-design-d82d4a625801

Motion in Web Design the Smart Way
https://blogs.adobe.com/creativecloud/motion-in-web-design-the-smart-way/

Motion in Web Design the Smart Way
http://uimotionkit.io/

Avoid Inline Scroll Areas (26% Get it Wrong) – Articles – Baymard Institute
While tech savvy users may be able to make these distinction, and most regular users eventually work out the conceptual nuances (subliminally of course), inline scroll areas introduce a lot of needless complexity and mental overhead to the page – before the user has even started interpreting and interacting with its actual contents.
http://baymard.com/blog/inline-scroll-areas

Web Usability Research at Microsoft Corporation
http://research.microsoft.com/en-us/um/people/marycz/webchapter.html

Simplify the virtual “landscape” for users so that spatial information can be easily learned:Designers should not overload pages with choices; as a general rule, five choices per page are sufficient, unless they can be grouped as a single chunk of information. Designers should make all choices in an image map fit in one screen. Directories and table of contents pages must have intuitive and recognizable ways of grouping and organizing entries. If a navigation bar contains both links to places and access to tools, the design must highlight the difference between these button groups. Designers should avoid nested scroll bars, and should especially avoid placing a nested scroll bar next to a major scroll bar. When using scrolling, designers should signal that there is additional content below or to the side.

7 USER INTERFACE DESIGN HABITS TO KICK IN 2013
https://blog.gfk.com/2012/12/7-user-interface-design-habits-to-kick-in-2013/

Usability implications of partial page scrolling
http://stackoverflow.com/questions/2950290/usability-implications-of-partial-page-scrolling

Introduction to Good Usability
http://temza.com/e-books/introduction-to-good-usability.pdf

The Extinction of the Scrollbar
https://uxmag.com/articles/the-extinction-of-the-scrollbar

In-page scrollbars – Yes or no? Or maybe
http://ux.stackexchange.com/questions/58499/in-page-scrollbars-yes-or-no-or-maybe

https://www.thebestdesigns.com/collections/best-20-websites-with-slick-video-backgrounds