Welcome to the forum! There’s a wk resources list thread you can find here The Ultimate Additional Japanese Resources List!
You’ll see threads about them being posted in from time to time in the suggested topics section below.
Personally I use Torii and Houhou for vocab. There’s also Kitsun (paid) and Floflo which you may or may not like better. Torii and Kitsun do the 10k vocab as well as kana/vocab outside of wanikani, they have JLPT vocab lists too. Houhou is basically a dictionary that uses jisho.org which you can do srs on by searching up words and adding them to the srs queue as you encounter them in your daily life. Floflo.moe is similar but has the incredible addition of organised decks for certain manga/novels/anime, so if you want to say read sword art online then you can learn the japanese words just for that novel. It only has a limited number of decks though as the author Raionus is constantly updating and has to add every new deck himself. In fact he’s overhauling the website as we speak I believe, and wishes to change the name to Koohii so keep an eye out for updates. The threads for the apps are the best place to check.
For grammar there’s Bunpro and Bunpo. I have bunpo on my phone and wish they had a website but oh well. Bunpro is great as an srs addition to grammar you learn elsewhere but as a standalone app for learning grammar I wouldn’t recommend it but you can try it out (1 month free) and see for yourself. You may find you’ll really like it.
There are also reverse wanikani apps (EN → JP, since wanikani only teaches JP → EN) Kaniwani and Kamesame if you’re looking for that sort of thing.
There’s also Tsurukame for iOS and Flaming Durtles for Android apps that allow you to do wanikani on your phone.
I’ve just mentioned the ones I know but I’m sure there are others you may find interesting in that ultimate resource list so check it out if you can!