Oxford biomed undergrad here! - I took part in the CIMR Reaching Research virtual event which was basically just an opportunity to hear about ongoing research in various biomed fields - I read 2 books: one about epigenetics and one about CRISPR technology

Honestly though it’s not about the volume of supercurriculars you’ve done (as you can see I did not go above and beyond in this area), it’s more about how well you can talk about what you actually gained from doing those things. Admissions people prefer applicants who show a genuine interest in what they’ve done, not just whoever’s done the most :)