• Obsidian - great markdown-based note app
• NewsFlash - fast and elegant RSS news reader
• Bottles - program to run Windows apps and managing them easily
• BreakTimer - a life-saver for me; it allows you to set a break after given amount of time
• LibreWolf - privacy-focused fork of Firefox

There are a lot of awesome programs on Linux, I recommend browsing Flathub to find them