Using automated tools to "scrape" or "check" usernames is a violation of Discord’s ToS. This can result in your account—and any rare username you manage to claim—being permanently banned.
While there are many tools available, some popular ones include: discordusernamecheckermainrar high quality
The most common payload. The checker may ask for your Discord token to "authorize" the tool. Instead of checking usernames, it sends your token to a hacker, who then steals your account, nitro, and servers. Using automated tools to "scrape" or "check" usernames