SAK's Channels (partially found videos from series of YouTube channels; 2008-2018)
The SAKS channels were a group of collaboration channels on YouTube owned and run by Ian Rylett. Each channel primarily had seven girls, with boys appearing once in a great while on certain channels, one for each day of the week that would do videos related to the channel or week theme on their assigned day of the week.
The SAKS channels combined held more than 15 million subscribers. The network of channels included SevenSuperGirls, SevenPerfectAngels, SevenAwesomeKids, SevenFabulousTeens, SevenFuntasticGirls, SevenCoolTweens, SevenTwinklingTweens, SevenGymnasticsGirls, and SevenEpicDancers. All of the channels featured girls younger than 18. 
The first SAK's channel, SevenAwesomeKids was launched in March of 2008.
The SAK's channels were terminated by YouTube on March 12th, 2019. The channels were terminated due to the charges of child molestation held by the owner of the channels, Ian Rylett. He allegedly forced one of the under-aged channel members to undress in front of him, then allegedly fondled her breasts with an attempt to take off her underwear. The victim of the alleged charges then later spoke up about her experience and more dark truths of the SAKS channels in her video "I'm the Victim...The SAKS Channels." 
Where to Find Them
Captures of the channels can be found on The Wayback Machine, but no links appear to lead to any of the content. 
A subset of the SAKs channels videos can also be found on archive.org, by searching the names of the SAKs channels.