Euro coins have common and national sides.
The 10, 20, and 50 c. coins circulated in Spain show Miguel de Cervantes Saavedra.
You can build quite a collection, as Spain is one of many countries that includes the year in which the coin was minted in the design. They exist for each of the years 1999 through 2023. So, there are 75 of them already.

In 2005, Spain issued a set of gold and silver commemorative coins for the 400th anniversary of the (first part of) the Quijote.