Examples are always plural in English

When we give examples in our sentences, the examples given should be plural unless the nouns concerned are uncountable. Let us look at the following sentences for illustration of my point here.
1 We can see quite a number of animals such as tigers, lions, monkeys, crocodiles, deer, rhinoceros and bears in a zoo.
2 Things sold in this supermarket include sugar, salt, shirts, cups, spoons, and others.
Note that deer is plural while sugar and salt are uncountable nouns.