With all that was said before, it should be clear that ordinal numbers have also a plural form. The tables above also show the plural forms of the declensions in the different categories. Only for being complete you will find some examples here.
Plural of ordinal numbers
Die Ersten
die kamen, beschwerten sich. = The first ones that came complained.
Die vierten
Plätze bekamen gar nichts. = The fourth places did not get anything.