At the top of the Contacts screen there is a Find Entry search bar that allows you to look for a specific contact, or narrow the searches from the full list of contacts if you are looking for a common feature of certain contacts

Enter the term that you want to filter the search results by and click Find button to the right of the search field.

Find contact

Once Find has been clicked, all contacts with the combination "Ha", in this example, will be presented.

Contact search results