Smart Collection Pro

I was skeptical because there was only 1 other review but I can say now that this app is amazing! It adds the functionality of being able to mix "AND" & "OR", nested collections and way more options for filtering. They're also quick to respond and open to feedback on adding functionality and new features. Awesome!
Do a free trial, you won't regret it.

Amazing app that provides really useful conditions and filtering to collections unlike the terrible default smart collections Shopify offers. Creating complicated collection filtering is really easy and the customer support is truly excellent. I had only a couple small problems whilst first setting up the collections but after reaching out to customer support through the live chat feature I received almost an instant response and my issues were immediately fixed. The app is relatively new but already so useful I'm really excited to see what happens in the future and would definitely recommend this to anyone wanting to organise their products into proper collections.