Stamps With Words And/Or Numbers As The Main Design

This 5.00 kroner stamp (Facit #1089) was issued by Denmark onAugust 19, 1993 to promote its letter writing campaign. Stamp says, "Have a letter...write one yourself!"

Uruguay
60th Anniversary of the Uruguayan Institute of Technical Standards
November 3, 1999
The main design shows 60 años and UNIT.

Here are two recent stamps for use by qualifying non-profit organizations in the USA. These organizations may mail non-first class, printed material at a greatly reduced rate.

The stamp (Sc #5061) on the left was issued on April 29, 2016, and its cost/value was 5c at the time of its release. The stamp (Sc #5172) on the right was issued on February 10, 2017, and cost at issue date was still 5c.

Ecuador
Football World Cup USA
June 10, 1994
One of the stamps in the minisheet shows text COPA MUNDIAL USA 94.

On December 1, 1923 Germany issued this set of six rentenpfennig-denominated stamps (Mi #s 338-43) in its new currency. These stamps used the October 1923, hyperinflationary "denomination in circle with rosette scrollwork" design.

These March 21, 1942, 10 centimes stamps (Sc #s 281-3) of Switzerland promote recycling in the French, German, and Italian languages. There are different numbers of each stamp in the full pane, with the German (Sc #282) appearing the most, and Italian (Sc #283) appearing the least.

This September 20, 1993 14 franc "anniversaries" stamp (Sc #903) of Luxembourg commemorates the centenary of the Artistic Circle of Luxembourg (CAL).

From petitfute.co.uk, "It exhibits its members painters, engravers and sculptors in different places. Every year, it organises an important exhibition during which the Grande Duke Adolphe Prize is awarded to the best work of art."

On May 9, 1977 Ireland issued this 8 p stamp (Hib #C235) to commemorate the centenary of the founding of the National Library. Stamp depicts a close-up view of a 16th century Irish manuscript.

Here is the 3000 leu value (Sc #4531) from Romania's August 9, 2002 "Post and Philately" set of five stamps. Stamp says "news travels".

On November 24, 1953 South Vietnam issued this 4 piaster airmail stamp (Sc #C2).

United Nations (Vienna)
45th Anniversary of the United Nations
June 26, 1990
Set of two, one stamp shows the numeral 45 as the main design.

Here is Luxembourg's 12 fr stamp (Sc #768) issued on March 9, 1987 to publicize the 50th Perspex International Fair.

Some examples of the early stamps of Brazil.

Possibly the first occupation issue from the Franco Prussian War of 1870-71.

On May 3, 1983 Luxembourg issued this two-stamp set (Sc #s 691-2) depicting illuminated letters from the Giant Bible of Echternach Abbey. The stamps depict the illuminated letters "L" (8 fr) and "B" (35 fr). The Bible dates from ca. 1050-80. It is now at the National Library of Luxembourg.

From wikipedia, "An illuminated letter was usually the first letter of a page or paragraph. It was always enlarged and in color with gold applied in areas, while the rest of the text remained black."