Link to tag
From Shopify Wiki
link_to_tag(tag)
This filter creates a link to all products in a collection that have the given tag.
{% for tag in collection.tags %}
{{ tag | link_to_tag: tag }}
{% endfor %}
The above code creates a list of links for each tag of each product in the collection. Each link directs to all the products in that collection that is tagged with the according tag.
Example: A collection of "shoes" could have the tags "winter", "summer", "sport", and "fashion". When this filter is used with lets say the tag "summer" for the collection "shoes", it would then render the collection template with all the shoes in the collection "shoes" that apply to the tag "summer".