Tofugu's Learn Kana Quiz is a web app originally designed to be a quiz tool to help you solidify the kana knowledge from our kana products, such as the workbooks and web pages I introduced earlier. However, it would be a great companion for really any kind of kana-learning resource as what it does is allow you to practice whatever kana you want, as many times as you want. It also helps you to identify the characters you still have a hard time with.
The way it works is simple. On the main page, you get to choose the kana you want to practice by column (a set of three to five characters). You can check all hiragana or all katakana with a single button too, if you're already familiar with all the kana listed.
During the quiz, you'll be prompted with a set of the selected hiragana characters and asked to type in the readings for each one. You can choose to skip items so you can save the ones you have a hard time recalling and circle back on those later. We believe the act of recalling is important, so unlike any other quiz tools, we actually won't tell you the correct answer even when you get things wrong. (We intentionally make it hard to cheat, and it's all for you!) However, you can try answering the same item until you type in the right answer so you can test your recall over and over.
Then, when you finish a session, the results show you how many failed attempts you had with the characters you couldn't answer correctly at the first go. This will help you identify what kana characters are not still sticking in your memory so you can do something about them — revisiting the mnemonics, inventing new mnemonics, or tracing the characters — whatever you gotta do to finally remember them!