Pretty much any two lines can come after this, as long as the last word of the last line rhymes with "Blue." A few examples are...
Roses are red and violets are blue, Got kids in my basement and I'm coming for you!
Roses are red and violets are blue, Your mom is gay and so are you!
and the most common...
Roses are red and violets are blue, sugar is sweet and so are you!