If you need to create a country list in K2 as a dropdown list extra filed, this will take a long time to enter countries one by one in the extra field edit form, this tutorial helps you to create such field in minutes
DM Categories Dropdown allows you to list K2 categories inside a dropdown or a listbox within a Joomla module. You can choose to list categories (and, if you want, their subcategories in a structured list) having a particular parent. In addition, the module can show an intro text, a link at the bottom, the articles' creation date. You can choose to have the active item always selected; SEF is supported with native Joomla API.
DM Articles Dropdown allows you to list K2 article titles inside a dropdown within a Joomla module. You can choose to list titles belonging to a K2 category or having a particular keyword.
With DM Articles Dropdown you can decide to show the articles' date and format it exactly as you need, setting its font style, its position, its format and so on. In addition, you can choose to display a bottom link, allowing you to provide a customized "read more link" to your module.