Add a 'most used' tab below the template search field in the template insertion dialogs (in VisualEditor and MediaWiki-extensions-TemplateWizard), that shows the most used templates.

Template transclusion frequency would be the simplest way to determine "most used", but this will in many wikis result in utility templates being shown (e.g. Template:WikiProject banner shell or Template:Yesno). So a more nuanced count might be better, e.g. only count direct transclusions in content pages.

Note that this task is not aiming to list a user's most-used templates (there doesn't seem to be a task for that), nor their recently-used (that's T347370: Add list of recently-used templates below template search form).