https://attra.ncat.org/attra-pub/internships/
This website is oriented more for people looking to make farming a career/lifestyle choice. There are wwoof type opportunities available, but many are exactly as stated internships and apprenticeships. I have contacted by email 4 farms through their listings on this site and found them to be very professional. Many require resumes, references, background checks or other preemployment screening. This is the norm, not the exception.
It make take some work, but I am confident this resource will be useful for anyone serious about working on a farm. There are many start ups and non conventional farming communities looking for help year round, just be prepared to make a commitment.