Windows Alternatives
Creative Apps
Newer Photoshop and Illustrator do not work well with Wine, versions XS6 and below are usually fine. Photoshop Lightroom does work with Wine versions 11.10 and above with the staging patch set.
Krita https://krita.org/en/download/
FireAlpaca https://firealpaca.com/
FTP Clients
WinSCP does work well with Wine.
FileZilla https://filezilla-project.org/
Media Players
mpv https://mpv.io/
Foobar2000 (requires Wine, works well) https://www.foobar2000.org/windows
System Utilities
WinRAR/7-Zip
Ark is built in to most KDE installs 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
Both do the same thing but have a slightly different interface.
Solaar https://flathub.org/en/apps/io.github.pwr_solaar.solaar
Pipe https://flathub.org/en/apps/org.freedesktop.Piper
Corsair Devices
CKB Next, does not support all corsair devices, check the supported hardware on the linked GitHub page https://github.com/ckb-next/ckb-next
Stream Deck
OpenDeck, uses Wine to try and run Stream Deck plugins designed for windows https://github.com/nekename/OpenDeck
StreamController, does not attempt to run Windows versions of plugins, smaller app store https://flathub.org/en/apps/com.core447.StreamController
RGB Software
OpenRGB - has to have specific support from the developers but a lot of devices are supported https://openrgb.org/
FPS overlay
MangoHud, similar to RTSS https://github.com/flightlessmango/Mangohud
Emulators
RetroArch, also available on Steam https://www.retroarch.com/