How to easily create a landing page for contents with specific tag
You can still do this easily with view panes. They play very nicely together with panels.

First step is to create the vocabulary you want to use / filter on. Then create a view pane with this vocab as an (exposed) filter.  By exposing this filter when a user adds this view pane to a panel, that exposed filter becomes a pane configuration option.  You can even expose content type as a filter and the user can choose what content types and terms they want to filter on when they add the pane.