For a free MS Office replacement, Libre Office. Avoid Open Office, because it is pretty much a dead project (Libre Office is the "fresh" off-shoot of Open Office, and very well supported and developed)
Avoid the Adobe Reader, and install an alternative instead. PDF Exchange Editor is my preferred one, and the free version even includes various free functionality which is normally only available in commercial PDF software. Super fast as well.
Excellent code editors: Visual Studio Code, Atom, Notepad++
Drawing/painting software: Krita (which include G'MIC effects)
Image editing: GIMP, Krita
Pixel art editors: GraphicsGale. Or AseSprite, because you probably know how to build apps since you are used to Linux (AseSprite is free if you build it yourself).
3D software: Without a doubt Blender.
Vector drawing: InkScape, but LibreOffice also includes a drawing app which includes a diagram editor.
Game Dev: Tiled, Godot Engine, Materialize, Git, SmartGit
Animation: OpenToonz, Krita, Davinci Resolve, DJV Imaging, DragonBones
Screen grabbing and recording: Greenshot, OBS Studio, FRAPS
Sound and music editing: Audacity, Reaper (indefinite trial, full functionality), LMMS. Scores of free VST instruments online.
Video editing: Davinci Resolve, Handbrake
Office: LibreOffice, PDF Exchange Editor, SumatraPDF
Media playing: VLC Player, Winamp,
Web Dev: XAMPP and/or WAMP, MySQL Workbench, Visual Studio Code, Firefox Developer, Filezilla, GIT, SmartGit, Nodejs/npm and all that jazz
Misc other tools: Irfanview and XNView (image viewers), ColorQuantizer for image optimization, DJV Imaging (Real-time image sequence and movie playback), 7-zip (archive tool)
Save your health utilities: PangoBrightness, f.lux
Windows system utilities: ProcessExplorer, Autorun, HWmonitor
Games: Too many to list. Install Steam, install emulators, visit abandoneware sites, and go from there.
A very handy all-in-one software installation tool to speed up installation of a list of mentioned tools is Ninite:
https://ninite.com/
This should get you started.