There are some names that can be both countable or uncountable:
Countable and uncountable nouns 1 (English Room)
Countable and uncountable nouns 2 (ECEnglish)
Countable and uncountable nouns 3 (University of Victoria)
Nouns + articles and quantifiers 1 (Liveworksheets)
Nouns + articles and quantifiers 2 (Liveworksheets)
Some/Any + There is/are (Liveworksheets)