Are you looking for high quality lessons (using Common Core Standards) for math and ELA? LearnZillion took their team of "amazing teachers" and has posted close to 2,000 lessons online at no cost.
You may search for math lessons by typing in key word as well as grade level, domain and standard. ELA lessons may be searched by topic (grammar and idioms, phonics, reading, writing) as well as as well as grade level, strands and stanards.
Lessons may include videos, slides and lesson commentary.
Via Beth Dichter