In primary, I did piano, elocution and gymnastics after school. One in school building but not a school organized activity, the rest separate. We did "swim week" every summer in the sea. And I remember sporadic terms of tennis coaching.
In secondary, I continued piano for a year but changed to guitar then, kept on elocution, started Girl Guides, and also did hockey after school (that was the only "in school" activity). I got involved in rowing in my later teens. But I always read a lot too once I actually learned how to read. And I had days when I had no activities.
DD does a bunch of stuff after school as the PTA organizes classes on a huge range of both indoor and outdoor things. So she does or has done Italian and Playball (afterschool club in crèche for about 2 years); guitar and French (both for 1 year), chess (for 2 years); hockey, athletics, soccer and gaelic games (all for 4+ years). And separately to "related to school" activities, she as done gaelic games and hockey in clubs, Coder DoJo computer coding, Cubs/Scouts, and sailing (these latter nothing to do with school and not all at the same time - so she's only doing 2 of those now). And school have been good about opportunities to do gardening, science projects (doing and exhibiting), choir, and lots of sports teams entered into events outside of core teaching the curriculum.
We are really lucky that the PTA has such a range of things to try, and childcare worked out to let her try them. But she also has times when she has nothing and gets her downtime as well. And we've been happy to allow her have activities on each of the 4 afternoons PTA have sessions if she wants, or not, and to change the activity (they have 2 terms per school year and you don't have to do the same thing for each half of the year but can change or drop out if you'd like at the halfway mark - as DD has done for various reasons over time).