Take a look in the Storybook for all the pre-built UI elements.
https://developers.arcgis.com/experience-builder/storybook/?path=/docs/components-jimu-ui-index-card...
You also have access to Bootstrap, which is very useful for implementing a Grid and many other things.
https://getbootstrap.com/docs/5.3/layout/grid/
GIS Developer
City of Arlington, Texas