Keeping with our frog theme, Suiren.io (睡蓮 means "lily pad" in Japanese) is a site that lets learners hop from one piece of information to the next (like a frog on lily pads), hopefully learning new things from a unique perspective.
Entering a word into the search bar pulls up a series of similar words related by their kanji, branching out into different possible relationships. Hovering over a character will highlight all its instances, letting you fall down a rabbit hole of new words. The bottom left corner shows the selected word, its kana, and the most common English meanings.
While it isn't a standalone tool, it's really fun to explore and you may be able to find some new words to add to your daily studies this way. This could be especially useful if you're having trouble remembering a certain kanji reading and want to see more examples of words that use the same one.
Just watch out, not every word is on the site, so if you look for your friends 鰐 and 蟹 you won't find them here (for now).