I died for beauty; Because I could not stop for death
Walt Whitman - Referred to as "The father of free verse", his work certainly challenged the status quo of his day. He first published his Leaves of Grass with his own money (self-publishing pioneer?) and continued to update it his whole life. Try these out:
Selections of Song of Myself
ee cummings - With his odd meter and unconventional use of lowercase, Cummings was a prominent voice of 20th Century poetry.
I will be; In the rain