The macOS setup for everyone (with free software only)

I prefer brave over Safari. It blocks ads and trackers by default. I just disable the optional cryptocrap !

Worth mentioning :
Mozilla Firefox (with uBlock Origin)
LibreWolf Firefox but more private by default
Orion Browser In closed-beta but promising browser.

If like my you use multiple browsers daily this one will be useful. Set it as your browser by default and when clicking on a link it will prompt which browser you want to open.

I prefer it over QuickTime Player and even the king VLC Media Player (still a great media player for macOS). It has beautiful modern design, Touch Bar support, System Media Control, Customizable UI, Online Subtitles, Music Mode, Mouse & Trackpad Gestures, Thumbnail Preview, Plugin System.

Based on the worth mentioning MPV

If you read ePUB on your Mac I would recommend you this one.
For manga lovers check : HakuNeko

Worth mentioning :
Thorium Reader AudioBooks also supported !
YACReader Comics focused
calibre

I do prefer this Mark down text editor over TextEdit !

If you need advanced PDF features for free ! (mention as bundleware on AlternativeTo) Preview works great if you just need to open and read them.

Worth mentioning : PDFsam Basic features on free tier

Way better and faster than the built-in Archive tool

For casual gaming on my MacBook !
GOG GALAXY DRM-free games so you own them for real.
Epic Games Store They gives free games every week, and 88% goes to the game editor/dev
Origin For the sims
Battle.net App Why not
itch.io BE CAREFUL TO DOWNLOAD TRUSTED GAMES BECAUSE SOME UNKNOWN SHITS ARE VIRUSES!!! ( more a thing on Windows 10 , but still)

If you want to play some PC games on your Mac !
It's a cloud gaming service so you need a good internet connection.
A lot of steam and Epic Store games (that you have to own) are available, but not all.
They have a free tier which is reasonable.

The best user friendly all in one emulator on macOS

Worth mentioning : RetroArch

If you want standalone emulators :

GBA : VisualBoyAdvance
NDS : melonDS
Gamecube and Wii : Dolphin Emulator
3DS : Citra

PlayStation : DuckStation
PS2 : PCSX2
PSP : PPSSPP
PSVita : Vita3K

Xbox (OG) : xemu

Master System : Mame
Saturn : Mednafen (MAME can also emulate saturn)
DreamCast : Redream

For more check : https://alternativeto.net/list/29770/the-ultimate-emulator-list/

If your friends game on PC, they probably use this one to communicate !

To play android game on your Mac

Worth mentioning : BlueStacks

If I have to do some image manipulation or photo editing ! (it's a WebApp)

Worth mentioning : GIMP with PhotoGIMP

If you do photography this is useful for photo editing !

Worth mentioning : Polarr

If you need to draw or modify vector images !

Worth mentioning :
Inkscape
Gravit Designer
Vectr WebApp

If you want to create font and make typography !

Worth mentioning : FontForge 100% free

If you want to draw !

Worth mentioning : FireAlpaca

If you want to do pixel art this one is gold !

Worth mentioning :
Piskel also in WebApp
LibreSprite BETA

Free lightweight 8-bit voxel art editor and interactive path tracing renderer.

Worth mentioning : Goxel

For 3D render and 3D animation. Nice UI, powerful tool and awesome community !

Worth mentioning : Blockbench Widely used for Minecraft modeling but it's easy, fast and fun to use but still gives impressive results !

For making video games or 3D environment !

Worth mentioning : Godot Engine

To quickly makes storyboard on Mac !