The free web debugging proxy for any browser, system or platform.
At the moment when you right-click on a line, you can select "Filter Now" in the menu and choose things like "hide this domain".
But my most needed filter would be "show only this domain" to hide all other requests which I don't care about.
The "Show only the following hosts" box atop the Filters tab is the way to go for now.
You won't be notified about changes to this idea.