We have the tools to do this quick but the rental market automated system is based off of the only data we have. Cards that are LISTED for rent. We do not have the data for cards that successfully get rented. And the issue is that means we are seeing all the mistake listings and then if a card gets rented out there is a giant hole in the market

"The rental market has more holes than swiss cheese"
We are seriously lacking cards at dozens if not hundreds of different levels.
And the only API we have is what is listed... Splinterlands will make a new API for rentals to give us more info but they're busy and we'll have to wait a bit so you'll need to put in a bit more work for the time being but it can still be fast with some good tricks.

SOME TRICKS

Find a ton of unlisted cards to list

Use the magic button

SAVE THESE CARDS FOR LATER

These are the ones that have no other card to compare them against

You can delete these ones for now and come back around to them later when you have time to research a price or just hope someone else publishes a price so you can put your price in compared to theirs.

These are the ones where there is only a mistake listing to compare them against.

VIDEO OF MY PROCESS

https://www.awesomescreenshot.com/video/4867013?key=0f4acd4eddabb7eb032fb6ec7f2cff8a