GigaC

This plugin allows you to manage the WooCommerce coupons per users.

WooCommerce Coupon User Management

solvenium

personaldiscount

This plugins enables you create links with a coupon code that will be applied automatically.
If your shop URL is <code>https://shop.example.com</code> then you can add a coupon code in a query parameter like this <code>https://shop.example.com?coupon=WELCOME10</code>.
You can add the coupon code to any URL pointing to a page within yor WooCommerce store. It can be a homepage, product, category, cart, checkout or any other page.
<ul>
<li><code>https:\\shop.example.com\product\invisible-watch?coupon=vip-x4tz8</code></li>
<li><code>https:\\shop.example.com\product-category\new-arrivals?coupon=HELLO-4M1GO</code></li>
<li><code>https:\\shop.example.com\product-category\new-arrivals?coupon=HELLO-4M1GO</code></li>
</ul>
Example use case
A perfect case for Woo Coupon URL is when you want to offer a discount to your newsletter subscribers. 
Normally, you’d append a coupon code to the email, and your customers would need to copy and paste the code. 
With Woo Coupon URL you can now send a link with the discount code that will be applied when your customers click on the link.

Woo Coupon URL

Attach a coupon code to your URL and apply it automatically to the cart.

WooCommerce Coupon User Management vs Woo Coupon URL