Recently, I was asked what tools I use to make TCM and stay on top of the development.  Everyone's work process is a little different and I'm always trying to refine mine but in no particular order, here are the tools I rely on most for development and management:

Ren'py - The obvious answer.  Ren'py is free, robust, and does what it does very well.  There's a bit of a learning curve if you're new to Python or coding in general but it was very easy to pick up.  When I first started TCM I was pretty new to programming and was able to make a functional game in like, a weekend or two.  It doesn't give you complete freedom but if you need more structure than something like Unity, this is a good place to start.

Visual Studio Code - My personal IDE of choice for pretty much all of my projects, even web development.  It has a ton of language plug-ins with really good Intellisense assist, it's easy to customize for your specific workflow, has built-in Git integration and robust debugging, plus it has a huge community so if you need help with something it's usually not hard to find answers.  IDEs range from stupidly complex to really lightweight and VSC is a nice medium.  Plus it's free.

Adobe Photoshop - I'll start by saying there are a LOT of downsides to using Adobe products.  They're ridiculously expensive, for one, and Adobe has some business practices that I don't like + trying to utilize the community for help is absolutely impossible.  The Adobe Suite is a resource hog and demands constant updates and access to do so to function.  I have used GIMP in the past and have considered moving back to it but for now, various personal circumstances make it more convenient to just use the Adobe products.  Of course, I use Photoshop the most.  In-game graphics, UI elements, and even gifs for chapter updates are all made in Photoshop.  I also use Premiere Pro occasionally for video edits like the soundtrack videos and trailers and InDesign for ebook style publications.

Audacity - Robust audio editing tool that's also free!  All of TCM's audio and sfx are worked on in Audacity which has an easy-to-learn interface and a wide selection of tools.  Not only do I do a lot of file management and clipping with Audacity, but I also use it to add effects to my soundtrack as well, like when the music is muffled through the wall at Pitrats.

Pixabay, Pexels, Unsplash - My go-to resources for stock images.  Pixabay also has a wide selection of audio and their license allows you to use their media without having to credit individual creators.  Pexels and Unsplash require credits but have a noticeably higher bump in selection and quality so I've come to rely on them a lot as well.

Freesound.org - Top tier resource for audio snippets and sound effects.  It's free to use but you need to make an account and note the individual license on each file.

Incomputech - If you don't already know who Kevin Macleod is I advise you to familiarize yourself asap.  This guy writes really high-quality, cinematic music that's 100% free to use even commercially with credit.  He does all kinds of styles and genres and posts everything for free on his website and on his Youtube.  TCM's soundtrack would not be what it is without Mr. Macleod's immense contributions to free music online.  His work is so ubiquitous you can find it in many games, viral memes, youtuber/streamer content, and animations. 

Github - Even working alone I feel like some kind of branch/version management tool is mandatory for large projects like a game.  Github (and its desktop component) is free and easy to configure so it's what I use the most.

Slack/Discord - I much prefer Discord over Slack but use both.  Both are free but Slack deletes messages over 90 days old unless you pay which sucks.

Trello - Trello is a free Kanban board style organizational tool that lets you make lists with cards, checklists, color coding, assignments, and many other features that let you customize how you keep track of things.  There's a premium access feature that unlocks all features, but the free version has been enough for my needs for many years now.  I mainly use Trello to keep track of bug testing or continual developmental issues and I also use a separate board to keep track of chapter releases, weekly, and daily tasks (and even household chores).  I really need visual aids to help me manage my time and Trello (in conjunction with handwritten weekly to-do lists orz) helps me keep my shit together.   This is ESPECIALLY helpful if you need to share progress with other people in a succinct, efficient way.

Taskade - Another free organizational tool that I use a lot.  Mostly, Taskade is good at checklist-style planning and some mind map tools.  I use Taskade to make publishing checklists so that when I go through the process of uploading a chapter update, I don't forget any steps and it cuts down on mistakes or avoidable errors.   I also use it to help me organize the steps between drafting, fleshing out, editing, implementing, beta testing, implementing more feedback, etc etc.  Again, visual aids and tools are the most helpful for me so being able to see all the steps I need to take helps me minimize forgetting something important.

Miro - Miro is really flexible mind mapping software that I use for both TCM and for personal writing.  A free account gets you a limited number of maps to create but I've been able to work within those parameters without much issue, though their payment plans aren't that bad if you've got extra cash.  I use Miro for vague outlining purposes so I can plan what story beats need to be in each chapter cause having a high-level view of that keeps me from getting bogged down in the minutiae.