Here is a picture of someone doing a pigeon stretch
. Instead of on the floor I do them on a massage table at a comfortable height, one leg on the floor, the other on the table, gradually leaning more into the knee as it loosens up, switching back and forth every 30 or 45 seconds for about 3 rounds each time I do them.
And here is a picture of someone doing a hamstring doorway stretch
. I don't do them with my shoes on, though :).