These emojis illustrate what people do in their free time. Simply put, hobbies. I'm not a fan of this term, so let's say, leisure activities. It can be sports competitions, card or computer games, festive events, art-related activities.
Of course, a lot of these activities have become old-fashioned. What normal person would knit or go fishing voluntarily? Soon such activities will go extinct and these emojis will be the only reminders of them. All progressive humanity has already realized that the best way to spend your free time is to chat on social media. That's what all these emojis have been designed for.