Is there a way, currently, without clicking into each item one by one, to show which items are not listed to a particular marketplace or any marketplace at all?
Ecomdash did this well when I was with them. On your inventory page, it had a little icon for each of your linked stores. For example, I'd have two eBay stores, one Etsy, one Amazon. If an item was listed on one of the eBay stores and Amazon, you'd see the eBay icon and Amazon icon next to the item, and if you clicked on the icon you were taken to the marketplace listing.
If the item somehow was not listed to any marketplace at all (say a listing was removed or ended, or you took down your winter clothing in March and it's September now and you want to relist...), there was no icon at all there.
I hope that makes sense. As it is now, I do see how to run a report that lists all the items that are in a store, and which store they are in, but that doesn't tell me which aren't in stores at all. Or you have to click on every individual item and go to the stores tab -- if you have the marketing integration, I think, is the only time that works. That's really a pain to click through hundreds and hundreds of items, as you can imagine.
Any help with this is appreciated!