Custom option renderer
An option_renderer snippet customizes both the options list and the selected value. This one uses the library's flag components, with Cyprus preselected.
<Select
field={my_form.fields.country}
placeholder="Country"
{options}
default_value="CY"
>
{#snippet option_renderer({ value, label })}
{@const Flag = flags[value as CountryAlpha2]}
<Flag width={20} height={20} />
<span>{label}</span>
{/snippet}
</Select>