This is the 14487th most frequent Turkish word.
oyuncakları
"Toys" (possessive: his/her/its/their toys).
In this sentence, 'oyuncaklarıyla' means 'with their toys', denoting possession and the instrumental case.
Çocuklar oyuncaklarıyla parkta oynuyor.
The children are playing with their toys in the park.
Here, 'oyuncakları' refers to 'the toys', acting as a direct object in the sentence.
Oyuncakları toplamak için kutuya koyduk.
We put the toys in the box to tidy them up.
In this example, 'oyuncakları' means 'these toys', and it is used as a direct object with a demonstrative pronoun adding specificity.