finna.fi is a Finish aggregator of cultural heritage managed by the National Library of Finland. In contains collections from Libraries, Museums and Archives across Finland.

There is a direct link that will take you to a search which filters for items with IIIF manifests. To get to this search go to the advanced search page and scroll down to the “Media type” filter and select “IIIF”.

Once you have found an item that has a IIIF manifest, you can should see a IIIF icon on the botttom right with a clickable menu called IIIF Tools. Clicking open in a new window will open the Manifest in a new window and copy to clipboard will copy the Manifest URL.