These are top and recommended Store Credit Extensions For Magento 2 Ecommerce

1) Landofcoder Store Credit: Magento 2 Store Credit will make the process of purchasing and refunding easier and faster than ever by online credit. Admin can control the transaction from the backend and increase the interaction with customers.
Link: https://landofcoder.com/magento-2-store-credit.html/

2) Mageworld Store Credit: The Magento 2 community store credit will encourage buyers to purchase and increase the performance in paying on your website.
Link: www.mage-world.com/magento-store-credit-extension.html

3) Mirasvit Store Credit: Store Credit & Refund Extension covers and automates most of your store activities, related to Credits and Refunds to customers
Link: https://mirasvit.com/magento-2-extensions/store-credit-refund.html