The WPForms plugin uses the following custom database tables for data storage;
The database prefix will differ depending on the table prefix defined in your site’s wp-config.php file.
The WPForms plugin has an uninstall option which can be found in the settings menu in wp-admin;
WPForms > Settings > Misc
You can confirm that the WPForms database tables have been deleted by verifying using a host-provided application such as phpMyAdmin or a plugin such as SQL Buddy.
It is always recommended to clean up plugin data when switching to alternatives before you run into leftover data in your site’s database.
When you review existing data stored in the site’s database, it becomes harder to deal with database cleanup. It is also not recommended to be running multiple-form plugins.