1) Landofcoder Magento 2 Store Pickup:
Magento 2 Store Pickup is one of must-have extensions for store owners to engage a majority of customers and boost conversion rates and sales. With integrated Magento 2 Store Locator, your customers can find out the most suitable stores in the checkout page and schedule to pick up desired items conveniently.
Link: https://landofcoder.com/magento-2-store-pickup.html/

2) Magedelight: Magento 2 Store Pickup
Let your customers make an order online and pick up the same from offline point of sale at the scheduled date & time with store pickup extension
Link: https://www.magedelight.com/store-pickup-magento-2.html

3) Wyomind Magento 2 Store Pickup
Allow your customers to collect their orders in any of your points of sale with Pickup@Store for Magento®®2!
Link: https://www.wyomind.com/magento2/store-pickup-magento.html