Gravity Forms and CiviCRM
There are currently two Wordpress integrations that I know of:

1) Contact Form 7 integration, developed by CiviCoop, here more info about it, I haven't tried it yet but looks promising.

2) Gravity Forms integration (paid for add-on) developed by Civivip, link to their shop, it supports Contacts and Activities entities.

Edit

Here's the Caldera Forms integration that I'm working on (the one I mentioned in the comment), is still in progress but is usable, if anyone wants to try it I recommend doing it in test environment first.

Github repository: caldera-forms-civicrm

You will need the Caldera Forms plugin installed previously, and of course CiviCRM, for it to work.