TinyMCE and CKEditor still exist afaik.
It has an image upload plugin but I don't think it supports drag & drop.
Still, searching the web for something like "html5 wysiwyg editor" or "js wysiwyg editor" gives a bunch of results with several comparison articles, etc.
You can also consider using a Markdown editor. Not quite the same, but it's been adopted by a few companies (e.g.: the ghost blog editor) and F3 also has its Markdown class.