Lots of baby videos. Wonder if that's because 15 years ago phone storage was at a premium so only relatively important stuff got videoed. I'd image baby videos would be diluted amongst less important stuff in a 2024 sample.
YouTube was also one of the easiest ways to share family videos back then (the files were too large to be emailed, Google Photos didn't exist yet, pretty sure Facebook could share videos but the quality wasn't as good, etc).