I love Louis Theroux so I watched some of his documentaries in my designated relaxing time. I read about how to plan essays and about the GAMSAT essay criteria. I found random quotes that could be used in essays about a variety of topics. I wrote A LOT of essays to time. There is no time to be overconfident or arrogant. There were a lot of.
If you need to brush up, hands down the best book is the Practice Makes Perfect Organic Chemistry book by De Wayne and Greenbowe. It covers absolutely everything, getting gradually more difficult as the book goes on with masses of practice qs. It got me from 0% to GAMSAT level, and it has a no-bs sort of vibe about it. Amazing book.