Lesson Planet, a "search engine for teachers," allows educators to search "over 225,000+ ... online lesson plans and worksheets." Your searches can be narrowed down by keyword, grade level, overall rating, subject, theme and state standards.
I have used Lesson Planet over the last few weeks to search for various plans and printables, with topics including Easter, the water cycle, endangered species and natural resources. Although Lesson Planet brought up many different websites for me to choose from, I still found myself searching for appropriate plans and worksheets for us. I found that I had to pick a little from this one, a bit from that one, to make it fit exactly what I needed. I think it's nice to be able to search by grade level, but I quickly learned that wouldn't work for me. What your typical public school educator thinks is on point for a third grader doesn't always work for my "third grader." By leaving all the search filters open, I had much better success.
If you're a public school teacher, this site might be very helpful. If you're a homeschooler, it's great to be able to pull up lessons that fit your state's "standards" so you can steer clear!
You can try Lesson Planet for free for 10 days. If you'd like to subscribe, the cost is $39.95 a year. For me, I'd rather search the net and put together exactly what I want for free! If you'd care to read what other reviewers had to say, click the pic below.