Jakob Nielsen's 10 general principles for interaction design. They are called "heuristics" because they are broad rules of thumb and not specific usability guidelines.
Affinity diagramming has long been used in business to organize large sets of ideas into clusters. In UX, the method is used to organize research findings or to sort design ideas in ideation workshops.
The animation property in CSS can be used to animate many other CSS properties such as color, background-color, height, or width. Each animation needs to be defined with the @keyframes at-rule which is then called with the animation property.