How do people get accounts for account dumps

I have always seen account dumps for various things ranging from roblox accounts to epic games accounts. My only question is, where do people get all the accounts? It's not like they just spend time making a bunch of fake accounts and buying stuff on it just to give it away. I'm just curious on where they get them?

They crack them. Bruteforce, using tools and wordlists.

They find a database that is exploitable via SLQi Dumper and afterward they dump it and if the passwords are hash they crack the hashes with a program. After that, they just use a program to brute force such as Snipr, and SentryMBA.