Mana Pool's sealed catalog is based on the open source MTGJSON project. If Mana Pool doesn't have a product you wish to sell, you can add it to MTGJSON, and then it will show up on Mana Pool about 48 hours later and you can list your inventory then.

To update MTGJSON:

1. go look at https://github.com/mtgjson/mtg-sealed-content find the set file in the directory https://github.com/mtgjson/mtg-sealed-content/tree/main/data/products 
2. find the TCGPlayer ID for the product on tcgplayer.com
3. submit a pull request to update the set file - you either need to: A) add the product itself in the same format as you see others in that file, or B) just add the TCGPlayer ID if the product already exists 
4. here are some examples of our team doing this: https://github.com/mtgjson/mtg-sealed-content/pulls?q=is%3Apr+is%3Aclosed+author%3Aandrewljohnson 

You can see adding a product is a small task, but it involves understanding how to properly format the file the data goes into, and understanding how to submit a "pull request" to mtgjson-sealed. 

To submit a pull request (you could ask chatgpt to walk you through this): 

1. fork the repository: https://github.com/mtgjson/mtg-sealed-content 
2. download the code for your fork to your machine 
3. edit the appropriate file in a text editor 
4. push your changes to your fork of the repo 
5. create a pull request to merge your branch into the main repo from the github.com interface

For more information or help, join the MTGJSON Discord server: https://discord.gg/HMJKAB42V. The maintainers  help folks in the #mtgjson channel.