Royal warrant of appointment

Royal warrants of appointment have been issued for centuries to tradespeople who supply goods or services to a royal court or certain royal personages. The royal warrant enables the supplier to advertise the fact that they supply to the issuer of the royal warrant; thus lending prestige to the supplier. Royal families of the United Kingdom, the Netherlands, Belgium, Luxembourg, Monaco, Denmark, Sweden, and Japan among others, allow tradesmen to advertise royal patronage.
Suppliers having a royal warrant charge for the goods and services supplied; a royal warrant does not imply that suppliers provide goods or services free of charge. Royal warrants are typically advertised on company hoardings, letter-heads and products by displaying the coat of arms or the heraldic badge of the royal personage issuing the royal warrant. Warrants granted by members of the British royal family usually include the phrase "By Appointment to…" followed by the title and name of the royal customer, and then what goods are provided; no other details of what is supplied may be given.
Purveyors for current households.
Australia.
Royal warrant holders of the Court of Australia:
Belgium.
In Belgium the title of 'Purveyor to the Court' (Gebrevetteerd Hofleverancier van België/Fournisseur breveté de la Cour de Belgique) is granted to businesses who provide services or goods to the royal court. 
The list of 'purveyors to the Court' is updated every year. The king himself makes the decision who gets a title or not.
Some of the 'Purveyors to the Court' include:
Denmark.
Purveyors to the Royal Danish Court:
Japan.
Purveyors to the Imperial Household Ministry; after World War II, the permission system was abolished, but purveyors still exist today:
Monaco.
High Patronage of the Monaco Royal Family:
Netherlands.
In the Netherlands, the status "hofleverancier" is awarded to small and medium-sized businesses that have existed for at least 100 years which have a good reputation regionally. However, the companies need not actually supply goods to the court. At present there are at least 387 companies that hold this status, which can be renewed every 25 years. Companies designated as "hofleverancier" are further permitted to display a plaque on their premises attesting to their status.
In addition, certain companies are granted the use of the designation "koninklijke" ("royal" in Dutch). These companies are also allowed to incorporate a crown in their logo. Examples include:
Norway.
Purveyors to the Royal Court of the Norway: the status 'purveyor to the court' ("hofflevrandør") is no longer awarded. 
Romania.
Purveyors to the Romanian Royal House:
Uganda.
The Royal House of Bunyoro-Kitara awards royal warrants to businesses that deliver goods and services to the royal house on a regular basis. The royal warrant can be awarded by a grantor, either the King, the Queen or the Crown Prince. The Board of the Royal Warrant Holder Society advises the Grantors but each Grantor makes the final decision to grant a Warrant. A business may only receive one Warrant from a Grantor. The warrants of the Bunyoro-Kitara Kingdom are valid for one year.
Historical reigning households.
Bavaria.
Purveyors to the Court of Bavaria:
Brazil.
Purveyors to the Brazilian Imperial Family:
France.
Purveyors to the Court of France:
Italy.
Purveyors to the Italian Royal Family:
Ottoman Empire.
Purveyors to the sultans of the Ottoman Empire:
Portugal.
Purveyors to the Portuguese Royal Household:
Prussia.
Purveyors to the Court of Prussia:
Russia.
Purveyors to the Russian Imperial Family:
Yugoslavia.
Royal Warrant Holders of the Yugoslav Court: