A library of science videos (similar in style to Bill Nye) aligned to Next Generation Science Standards. Each video has discussion questions, lesson plan, teacher guide, and instructions for experiments. Subscription price is pretty reasonable.

A children's magazine, published in the UK and available world-wide. Each issue explores a topic, and includes interesting articles, colorful artwork, great information, and hands-on activities. Price is a bit high, but there's no advertising or "fluff", so it worth the investment.

This museum in Philadelphia has a great website with lots of educational resources. The interactive constitution lets you read articles and amendments alongside commentary from different historic and legal experts. There is also a collection of videos and lesson plans, and a few other interactive activities and games, plus primary source documents and even some craft ideas.

This wonderful, creative website encourages writing through art. Writers (of all ages!) choose artwork to inspire stories and poetry. There are tools for editing, and work can be published on the site or purchased in printed form. There are also how-to guides and courses to help in the writing process. Creating an account (as a teacher or creator) is free, and gives you access to all the writing tools. You can upgrade to a paid account for unlimited word counts and a few extra features.