Windows Alternatives

Creative Apps

Krita https://krita.org/en/download/

GIMP https://www.gimp.org/

FireAlpaca https://firealpaca.com/

FTP Clients

FileZilla https://filezilla-project.org/

Media Players

VLC https://www.videolan.org/

mpv https://mpv.io/

Foobar2000 (requires Wine, works well) https://www.foobar2000.org/windows

System Utilities

WinRAR/7-Zip

Ark https://flathub.org/en/apps/org.kde.ark

PeaZip https://flathub.org/en/apps/io.github.peazip.PeaZip

WinDirStat/SpaceMonger/WizTree

Filelight https://flathub.org/en/apps/org.kde.filelight

Disk Usage Analyzer https://flathub.org/en/apps/org.gnome.baobab

Gaming

Shadowplay

GPU Screen Recorder https://flathub.org/en/apps/com.dec05eba.gpu_screen_recorder

Minecraft Launcher

Prism Launcher https://prismlauncher.org/

Epic Games/GOG/Amazon Games

Heroic Games Launcher https://heroicgameslauncher.com/

Logitech Mice

Solaar https://flathub.org/en/apps/io.github.pwr_solaar.solaar

Pipe https://flathub.org/en/apps/org.freedesktop.Piper

Corsair Devices

CKB Next https://github.com/ckb-next/ckb-next

RGB Software

OpenRGB https://openrgb.org/

FPS overlay

MangoHud https://github.com/flightlessmango/Mangohud

Emulators

RetroArch, also available on Steam https://www.retroarch.com/