https://community.esri.com/t5/arcgis-hub-ideas/flexibility-responsiveness-gallery-cards-arcgis/idc-p/1094782#M314
Gallery is a great way to present a list of Viewers or Data or both. It's discoverable because sometimes people don't know what they are searching for; they need to see a list visually. It's very useful for almost any organization or town which wants to put their data on Open Data for the public to explore.
There are two main issues. One is lack of pagination. I hope that is added in an update, so we have arrows on each side of the Gallery and can swipe or click left or right to see more item thumbnails. https://community.esri.com/t5/arcgis-hub-ideas/add-pagination-to-gallery-widget/idc-p/1094779#M313
I am wondering, would it be possible to make it into a Bootstrap carousel with a CSS workaround? Maybe using a combo of iFrame and Gallery? Bootstrap carousels are very simple, but Esri doesn't expose the HTML and CSS of Gallery. (I wish we could see and edit the raw HTML and CSS of every Hub component; then this would be easy) Any thoughts?
Secondly - in Gallery if you have an odd number of items, like viewers, let's say three or five.. it stretches the bottom one very widely. It looks very bad. It also resizes the thumbnail image, and cuts it off. It does not look good. Is there a CSS workaround Esri could provide to stop the resizing?
Long-term, it would be good to have custom sizing on a per-card basis in a Gallery row; or at least disabling option for Gallery rows. Or allow access to raw HTML/CSS on all Hub components.