These are top and recommended Auction Extensions For Magento Ecommerce

1) Landofcoder Auction: Magento 2 Auction Extension supports to build a powerful Bidding Online System with attractive Auction Page in count-down timer, full management auction: clear bidding rate, easily create increments, automatic, Reserve Auction, import CSV
Link: https://landofcoder.com/magento-2-auction-extension.html/

2) Magestore Auction:
Look for a new way to get customers engaged more while shopping? Why don’t you create online auctions with Magento 2 Auction. This Magento 2 bidding extension will let your customers place a bid or auto bid for products.
Link: https://www.magestore.com/magento-2-auction-extension.html

3) Magesales Auction:
It Allow to use either Standard bid or Auto bid.
Link: https://www.magesales.com/magento-auction.html