In the world of account trading, "unchecked" lists are typically databases of usernames and passwords (often called "combolists") leaked from other websites.
If you want to play Fortnite with specific items, the only safe and legal methods are: Download 500 Fortnite accounts UNCHECKED NICE HITS txt
Accessing an account without permission is a violation of the Computer Fraud and Abuse Act (in the US) and similar laws elsewhere [7]. How to Safely Get a Fortnite Account In the world of account trading, "unchecked" lists