Rikaisama is an expanded version of the Rikaichan Firefox extension that allows one to see the readings and english translations of japanese text by hovering over it in your webbrowser. While discontinued and thus not fully stable with new versions of Firefox, it has the most features, such as showing pitch accent, a reading of words with a button press, adding words to anki at another button press, the option for a different dictionary, etc.

Paid: Free
Practicing skill: Reading
Web Version Available: Yes