Take a look around this site and you will find a ton of great resources. The first two sections shown on Kraft's site focus on verb and adjective conjugation practice. You can select which individual conjugation form you would like to practice or choose the randomized option. The system will then generate a verb and conjugation combination that you will have to come up with an answer to.
Another cool feature of this site is the numbers and counters practice. Here, you can test your knowledge of counters (like two birds or five machines), numbers, and time. You'll never be late in Japan because you misunderstood the time again!
How is your ability to type hiragana and katakana on the computer? You can practice by typing in the romaji that correlates with the character here too. How about your N5 vocabulary knowledge? Much like WaniKani, you can test your ability to recall the on'yomi, kun'yomi, and English meaning of various words here. If you're learning with Genki, Steven Kraft also has a whole section dedicated to supplementary content. You can currently work through exercises for lessons 1 through 9. Other sections should be added in the future.
One of my favorite projects on this site is called "Watch Japan." When you click on this page, a random video that is about Japan or the Japanese language will play. You can reload another video to see more or to skip to the next. There are currently 1121 videos and counting…! They are all under twenty minutes and can be understood by beginners. This site has plenty more to see, and since it's updated regularly, it will keep you engaged with new material.