themeszone

The plugin once activated will display a quantity field with increment / decrement buttons once add to cart button is pressed (e.g. the product is added to cart). 
Thus allowing customers to change the products number in the cart with out having to go to shopping cart 
page.
<a href="http://plugins.themes.zone" rel="nofollow ugc">PLUGIN DEMO</a> 
(click “Add to Cart button to see it in action”)
Feel free to ask any questions at <a href="https://themes.zone" rel="nofollow ugc">Themes Zone</a>

ThemesZone WooCommerce Ajax Quantity

ThemesZone WooCommerce Ajax Quantity Plugin shows quantity field on product listing once customer clicks "Add to Cart" button.

RLDD

Apply WooCommerce Coupons automatically with a simple, fast and lightweight plugin.
<h3>Features</h3>
☑ Unlimited Auto Apply Coupons using native WooCommerce coupon conditions
☑ Set Minimum Product Quantities for coupons
☑ Apply Coupons by URL when a specific page is visited
☑ Coupon Troubleshooting by itemized coupon on the cart page
☑ WooCommerce Blocks Compatible
<h3>PRO Features</h3>
✅ Auto-Apply Defaults – Default future coupons to auto-apply automatically.
✅ Bulk Updates – Update auto-apply on active coupons in bulk.
✅ Copy Coupons & More – Duplicate coupons, products, posts and pages.
✅ Streamline Email Restrictions – Prompt for customer email in cart when a coupon with email restrictions is applied.
✅ Coupon Defaults – Set default verbiage for new coupons.

Auto Coupons for WooCommerce

Apply WooCommerce Coupons automatically with a fast, lightweight plugin. Set minimum product quantities, apply coupons by URL or automatically.

ThemesZone WooCommerce Ajax Quantity vs Auto Coupons for WooCommerce