Datei:Flag of Austria (state).svg – Wikipedia

File:Flag of Salzburg (state).svg - Wikipedia

File:Flag of the German Confederation (war).svg - Wikipedia

Apparently, the flag of the Alash Autonomy was actually green-red-yellow, and not green-yellow-red : r/Kaiserreich

Template:Country data Hungary - Sarkarverse, the wikipedia of all things Prabhat Ranjan Sarkar

File:Flag-map of Germany (subdivisions).svg - Wikipedia

File:Flag of Weimar Republic (merchant+cross).svg - Wikimedia Commons

File:Flag of Vienna (state).svg - Wikipedia

File:SA Allgemeiner Wimpel.svg - Wikimedia Commons

File:Flag of Upper Austria (state).svg - Wikipedia

File:Flag of Denmark.svg - Wikimedia Commons

File:Flag of Taliban (variant).svg - Wikimedia Commons

File:Flag of Bosnia (1908–1918).svg - Wikipedia

I know it's a common trope but here's my unique take on Federal Austria-Hungary : r/imaginarymaps