ericjuden

This plugin allows you to use $_COOKIE, $_SERVER, $_SESSION, $_GET, $_POST and $_REQUEST data in a Gravity Form through the merge tags of a field. I’ve only really tested this using a hidden field.

Gravity Forms Extended Merge Tags

It's amazing how few people seem to know about this plugin. Incredibly simple, but also really helpful when using $_SESSION variables to track website visitors.
I use it to get referring website data, so I can easily store it in a $__SESSION variable. Then when the visitor fills out a Gravity Form, I can pass along the stored vars.
I crafted a Lead Source Tracking for Salesforce script that uses this plugin to pass along the details to Salesforce when a form is submitted.



Brilliantly simple

This plugin allows you to use $_COOKIE, $_SERVER, $_SESSION, $_GET, $_POST and $_REQUEST data in a Gravity Form through the merge tags of a field.

Firdaus Zahari

This plugin allows you to track all user devices used when logging in to your site. The user agent, login date/time, and logout date/time (if the users log out from the site) are tracked automatically and persisted into the database for later viewing.
You can find a list of all login devices available under the Users > Login Devices submenu.

FS Login Devices

Track and display all users devices used during authentication process

Gravity Forms Extended Merge Tags vs FS Login Devices