YouTube: YouTube provides embed code for videos. On a video's page click Share → Embed → Show More and uncheck Show suggested videos before copying the embed code. Furthermore, here's how to start the embedded video at a specific start time.
Explain Everything: Create narrated slideshows, screencasts, and animations using Explain Everything's iPad, iPhone, Chromebook, Android, or Windows app. Publish to Explain Everything's portal (called Discover). Then click the <> button that appears when you hover over the video to access the embed code. Unlike Educreations, Explain Everything embeds do not require Flash. Publishing to Explain Everything Discover requires a subscription.