Some are saying to learn 14 or 19
If they put 19 on it I'd be shocked as its came up twice in the past years, there's speculation it's 14 and we have every right to think it will be as it hasn't come up yet but I wouldn't rely on it
Technically you should really know all of them very well, but seeing as 14 and 19 are the longer more complicated ones spend more time learning those, especially since 14 is highly tipped to come up ;) Good luck!
make sure you know the cirlce theorim and piotagrus know at least one collary involved with each theorim and know th meaning of th terms collary and axiam and know an example of an axiam ie. the number of degrees on a straight lione is 180