lernu! is where I got started on my Esperanto journey. I like Duolingo better, but for a long time lernu! was the place to go to learn Esperanto on the internet. They still have a ton of great resources, and are worth checking out.
Developer Eric Demers from Ontario created a website with games that help you learn Esperanto.
bab.la has online dictionaries for 28 languages, including an English/Esperanto dictionary.
Bookbox uploaded several children's stories in Esperanto, with Esperanto subtitles.
Here's a playlist I found of Esperanto music on YouTube. I sometimes listen to it while working on my laptop.