This is the 5893rd most frequent Spanish word.
tractores
Tractors.
Here, 'tractores' is used as the subject of the sentence, referring to the machines operating.
Los tractores trabajan en el campo durante la cosecha.
The tractors work in the field during harvest.
'Tractores' is used as part of a possessive noun phrase, coming after 'una colección de' indicating the type of items collected.
Mi abuelo tiene una colección de tractores antiguos.
My grandfather has a collection of antique tractors.
'Tractores' is utilized here as part of a broader classification, following 'incluidos' to specify tractors as a particular item among others.