This plugin for Obsidian is a copy URL context menu in preview mode that works like the built in one in edit mode.
The plugin also works on mobile, but was only tested on Android.
The plugin was tested in Obsidian v0.11.13 and subsequent versions, but probably works with older versions.
You can install the plugin via the Community Plugins tab within Obsidian.
You can also manually copy from releases to your .obsidian/plugins/copy-url-in-preview
folder.
Thank you to the makers of the Tag Wrangler plugin, as it was a great starting point for working with context menus in Obsidian.