I’m using a WP Event Module called MyEventOn (https://www.myeventon.com/) in which each event will link to a gravity form for the visitor to complete a registration form.
What i’d like to do is to have a field to be pre-populated with the event name from the Events Module.
If the events are a custom post type you can use embed_post merge tag in the field default value setting to populate it with one of the post properties.
If they are implemented in some other way the gform_field_value filter can be used to populate the field. You would need to contact the developers of eventon to find out if they have a function you can use with that filter to get the event properties.