Related Options - to create combinations of related product options and set stock, price, model etc. for each combination. This functionality can be useful for sales of products, having interlinked options, such as size and color for clothes
Related Options PRO - improved premium version or Related Options module, which allows to create different combinations of options values per one product.
Product Options Image PRO - to set few images for each option value and show this images on the product page in dependence of selected option value.
Improved Options - to set SKU, model (product code), description for each product option value and set default product option values that should be selected, when customer opens product page.
Parent-child Options to show/hide child options (options groups) depending on selected parent options values.