Collection #1 is a massive credential-stuffing compilation built from thousands of earlier breaches. leaksear.ch indexes 2.69B records containing email addresses with plaintext or hashed passwords, creating risk for anyone who reused credentials.
A BestCombo/GGBestC credential stuffing list contains about 1.56 million plaintext email and password records advertised for popular gaming and streaming services. The data appears to be an aggregated combolist, not evidence of a direct breach at the named platforms.