Like how animations have [anim]/[webm] labels on the thumbs, I believe so should their be [slid] or some other abbreviation

I believe this would be useful as labels like these indicate from the thumb a post moves, and while slide shows might not move in the way of animations or interactive files there is still content happening besides what you can only see from the thumbnail. A lot of users end up miss-tagging slideshows as animations, and I believe that's partly due to them wanting the inclusion of the animation label to be present on the thumbnail.

This would effect any parts of the website where labels are visible in thumbs, like the main booru.