They usually prioritise Irish poets and female poets, so they dont look sexist or not patriotic. So I would say Heaney, Durcan, Bishop and Plath as well as one of the American male ones. Boland came up last year so I doubt she will come up again
Heaney and Durcan are both quite likely, as they are both due an appearance as they have not been examined the last three times that they were examinable.(Being Irish poets also helps). Boland is likely seeing as she is an Irish female poet and passed away recentley in April 2020, but it is also unlikely for the SEC to examine her 2 years in a row, so i'm not sure about Boland myself