@Snoe I would suggest Hemingway for grammar checking. There’s a free version you can use online in your browser if you don’t want to pay and download it. The cool thing about it is it checks the readability level, points out passive voice phrases, adverbs, highlights words with simpler alternatives, and “hard to read” sentences.
Scrivener is quite a powerful for writing, you can keep anything related to your project nice and organized: research, character/location sheets etc. It makes plotting and reorganizing scenes a breeze, and you can tag scenes with colors, short descriptions and which state they’re in (to do, first draft, second draft, complete etc) to keep track of things easily. Much better than having files scattered around a harddrive. Plus you can set it to track your wordcount per session, and set wordcount goals both for the entire story and per session, pretty useful to keep motivated.
On the downside, and one reason I don’t use it as much as I want is that you can’t really use it on multiple devices, there is no mobile app despite the developers announcing it years ago. I like writing on my phone/tablet often, and not being able to sync my progress is frustrating.
So for now I mostly use Evernote, I can create a similar organizing system for scenes and a separate folder for research, and it seems to be working out. The program wasn’t created with writing in mind particularly, so it lacks a lot of what Scrivener has to offer, like grammar/spelling checks and wordcount tracking, but I just copy-paste my content in Hemingway afterwards, to check things like that. Plus your content is automatically saved to the cloud, if your computer goes down, you don’t lose anything you were working on. The good thing about Evernote is that you can use it for free perpetually if you can work within the limitations of the free version. (Unlike Scrivener which I think only has a limited time free trial, then you have to pay.)
For coding I use Sublime on Windows, Textmate on Mac and Textastic on iPad, all of which sync together through iCould.
Edit: I was mistaken, the Hemingway app is not free, but the browser version is.