"Each" is a very specific type of condition which allows applying the discount only when Each of the combinations of the specified products is available in the cart.

It is more like a bundle product discount.
The discount will be applied only when each of the mentioned are purchased.

Here we have come up with an example like, Buy each Cap + Belt + Sunglasses to get the discount on all those products.

Let's see on how to set such a rule:
Navigate to Woocommerce --> Woo Discount Rules --> "Add new rule".

Since I am applying the discount on product prices, I am choosing the discount type as Product Adjustment.

Screenshot of rule setup 1:

Buy product A + B + C and get 10% off on all three products

The discounts will be applied in the cart when each of the mentioned products is added to the cart.

Note:

Rule setup 2:

Buy product A + B + C and get product D as free.

Also, to provide free product recursively (ie..,2A + 2B + 2C and get 2D as free and so on...) you might have to create separate rules for each increasing free product.

For 1D as free when customer buys 1 of A + B + C:

For 2D as free when customer buys 2A + 2B + 2C:

Likewise, you have to create separate rules for 3 free products and so on...

Note: This scenario might be possible only if product A, B and C are simple products.

Here is the cart page screenshot:

Video:

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