Unblocking at element-level in uBlock Origin
You can use the uBlock Origin's own logger for logging the network requests that got blocked or allowed in addition to the CSS rules that were affected by your filters.
Please assist this official overview of the logger from the official uBlock Origin own Wiki page: https://github.com/gorhill/uBlock/wiki/The-logger
Good luck.
For folks looking how to unblock elements they manually added themselves, you can click the uBlock icon, click the gear icon in the top left corner to go into the 'dashboard'. From there, go to the 'My Filters' tab and it will show you a list of all elements you've blocked manually.
Manually blocking elements is pretty handy for all those annoying social widgets that scroll with you as you read a page or little boxes that pop up in the corner these days referring you to read some other article on the same site.
But the site I was reading, I accidentally blocked the whole main content frame!! Thankfully with a bit of searching was able to get it unblocked....