The principle of design variety states that multiple contrasting elements can capture user attention. This is based on the human desire to indulge and explore and the fear of missing out.
Unity, balance, and contrast are similar sounding design principles that differ from variety. Designers can use variety to capture user attention, but too much variety can lead to poor usability.
Designers can use variety in multiple ways in UX designs such as using multiple colors, experimenting with a different font family, playing with size and space, using shapes, and using interactive animations.
Visual hierarchy can also create variety within the design.
Using excess variety can lead to clutter and frustration, which is why designers have to use it sparingly and with intention.