Hello everyone.
Is there any site or resource out there that groups together similar looking kanjis based on radicals. For example, 推・稚. As I’ve progressed further into the levels, I’ve found it quite difficult to distinguish certain similar looking kanjis and could use some help.
Best.
There are quite a few things that do just that. Just search for visually similar kanji on the forums.
There’s a userscript called Niai which expands on the visually similar kanji section that WaniKani already has: [Userscript] Niai 似合い Visually Similar Kanji, this website for looking up similar kanji, homonyms, and synonyms: Introducing Niai: Lookup similar Kanjis, Homonyms, Synonyms and this extension of the self-study script that let’s you study visually similar kanji: [Userscript] Open Framework: Visually Similar Kanji Filter.
There’s also the [Userscript] ConfusionGuesser which guesses which other item you might have confused a vocab or kanji for during reviews.
Also, if you really want to do this you can go to https://jisho.org/#radical (or another dictionary, lots of them have radical search) and choose the specific radicals you want to look for.
And see @ekg’s answer below for some better suggestions!
The Kanji Map is pretty cool. You can search for a kanji on the search bar on the right, and if you click on a component it links other kanji that use it, and also shows the info for the kanji selected.
Example:
If you want to train interference when it comes to leeches, I warmly recommend the Shin WaniKani Leech Trainer. It can be found on greasy fork here
and works wonders when it comes to training items that are visually similar.
Another way to work on the issue is using the Item Inspector
Since it integrates the Keisei-Phonetics script, you can just hover the cursor over items and you’ll get a pop-up with related items, that use the same radical = are visually similar.
Like this:
I find this very helpful for a quick review of items that I struggle with. ^^
There’s a handy website called Niai by a friendly WK neighbor @mrahhal
EDIT: Welp, it was already mentioned 
But at least I did the summoning.
The author of Item Inspector here. I want to pile on what @ekg said and point out that Item Inspector lets you study visually similar items in several ways.
One possibility is to request the visually similar items to be displayed in the popups. When you configure the popups elements you are given three options for showing the visually similar elements.
The effect of picking these options is to show the visually similar kanji in the popups for kanji items.
You may also search for visually similar kanji with the Related Search filter.
This will return the visually similar kanji as per your search parameters.
Thank goodness you’re here to explain things properly! 
I use kanjidamage.com (which also usually has helpful notes about usage), though you have to be okay with rude mnemonics.
Also, though these would be a significant monetary investment, the White Rabbit Press flashcards also note 1-2 similar kanji per card. And once I identify similarly looking kanji that I am confusing I take out my flascards and group them all together and study them, including common words and phrases they appear in. (You could probably do something similar with homemade flashcards or Anki, but I already have these and wanted to take advantage of them.
