Supported Browsers - I guess it's working well but not all browseres tested.

      @supported_browsers ||= [
        'Safari',
        'Safari Technology Preview',
        'WebKit',
        'Google Chrome',
        'Google Chrome Beta',
        'Google Chrome Dev',
        'Google Chrome Canary',
        'Chromium',
        'Opera',
        'Opera Beta',
        'Opera Developer',
        'Opera GX',
        'Vivaldi',
        'Vivaldi Beta',
        'Vivaldi Snapshot',
        'Microsoft Edge',
        'Microsoft Edge Beta',
        'Microsoft Edge Dev',
        'Microsoft Edge Canary',
        'Brave Browser',
        'Brave Browser Beta',
        'Brave Browser Dev',
        'Brave Browser Nightly'
      ]

Changes

Icon for workflow
Icons for search result: document.icns -> app.icns, compass.icns
Search Safari and Chrome Tabs.alfredworkflow icons just from alfred-tabs and applied above changes
If you prefer original icons, use SearchTabs.alfredworkflow

Search tabs in Safari and Chrome (also supports Safari Technology Preview, WebKit, Chromium, Chrome Canary and Vivaldi)

Just added Vivaldi support to Search Safari and Chrome Tabs by ClintonStrong.

Original : Packal, Forum

I hope someone figures out a way to support Firefox.