I have written many poems, topped lists and helped other poets.
Also, is a comma required after the word 'wells' here?
I spent years trimming flowers, digging wells and doing dishes.
the comma you mention is known as the Oxford Comma. Users of the English language have traditionally been split into opposing camps over the validity and usefulness; now it has largely come to be accepted as valid. While not required, the Oxford Comma may come in handy for avoiding ambiguities or emphasising the final item on a list. In your second example, for instance, 'digging wells and doing dishes' may be taken as an elaboration of 'trimming flowers' (compare to 'I spent years frequenting movie theaters, watching crime thrillers and taking copious notes'); if you add the Oxford Comma, this ambiguity disappears.