"isto", "isso", "aquilo".
These three pronouns may further be emphasized by using "aqui", "ai", "ali" respectively with them. There is no equivalent word in English except possibly the effect may be brought by using special emphasizing word.
Let's see some examples:

Isto aqui é um gato	This one,here, is a cat.
Isso ai é o meu amigo.	That one,there, is my friend.
Aquilo ali é uma árvore.	That one there(far) is a tree.