Magento – How to add unsubscribe link in custom email template magento1

Once you created email template you can get with below default code of magento source model

    <notification>
                <label>Select Email Template </label>
                <comment>It is advisable to create a new email template for this purpose and then select it in this configuration. Make sure you add review URL in your template. For e.g., {{ReviewURL}} <![CDATA[ <br /><span style="color:#FFA500">NOTE:- Default template from locale should not be used. Make sure you add product Name in your template. For e.g., {{ProductName}} You can also use other variables like OrderNumber {{OrderNumber}}</span>]]></comment>
                <frontend_type>select</frontend_type>
                <backend_model>mcautoreviewreminderemail/Mcautoreviewreminderemailtemplate</backend_model>
                <source_model>adminhtml/system_config_source_email_template</source_model>
                <sort_order>4</sort_order>
                <show_in_default>1</show_in_default>
                <show_in_website>1</show_in_website>
                <show_in_store>1</show_in_store>
                <can_be_empty>1</can_be_empty>
   <notification>

i am sure it will work for you.

Your call is subscriber.getUnsubscriptionLink(), but the function is getUnsubscribeUrl() (LINK vs. URL)