I know Sōseki is often recommended for reading practice.
I want to share a site I discovered that provides many resources for Soseki readers.
http://www.sosekiproject.org/
For example, here is the japanese text for the first few sections of Kokoro:
http://www.sosekiproject.org/kokoro/kokoro01.html
As you can see, you can hover over certain words and get a definition. There is also an audio recording of the story being read. If you want more, there’s a study guide with vocabulary list too. Anyways, I thought I’d share this discovery as I am spending a lot of time these days doing reading practice and could always use more resources like this.