TikTok is not about who you follow, it's about who you see. The money is in the For You page, the part of the app that responds to all your needs and wants. You might already have an annoying friend who guarantees they have the best For You Page and that they could curate yours if you like. That's just a good algorithm at work.
However, when you first join TikTok, you look for familiar features: the like button, the comment section, people to follow, and the hashtags. Who you follow and what you like play a huge role in shaping your For You page. Don't try to make sense out of the hashtags under a given post, the further you stray from Straight TikTok the less sense they will make.
The hashtags do, however, provide a doorway to a wealth of information and resources — if someone is offering expert advice, they're sure to always use the best hashtag. On the other side, more than any other platform, hashtags on TikTok don't really function like fixed categories, which means that every hashtag is guaranteed to have a lot of videos that are unrelated to that category.
Despite that margin of error, the following hashtags are just a small sample of the wealth of knowledge TikTok can offer.