Not sure if this is what you want, but the /collection URL shows all collections in your store. Not the products within them, just the collections themselves with their respective image and name.
Hey there Andrew!
Diana here from the Shopify Support Team.
I actually have a set of instructions that may help! This will allow you to feature your collections on a page using a menu; the images that will appear are the 'Collection Images' you set in the collections themselves. Take a look to see if this is what you're looking for:
Hope this helps! :)