How are you?
In this list I bring you a variety of alternative software to those from Microsoft, and also that these free and open source programs
So enjoy this list!
(I will be updating it every day)
Cross-platform email client providing POP/IMAP support, robust filtering, multiple accounts, and chat. Extendable via add-ons with RSS/Atom, etc.
Open-source client enhancing Thunderbird with more features and bug fixes. Offers security patches and multi-row descriptions like Outlook.
Boost your productivity and send better email with Mailspring, a beautiful, fast email client for Mac, Windows, and Linux. Mailspring is free to use and an optional pro version adds read receipts, send later, reminders and more.
Evolution is a personal information management application that provides integrated mail, calendaring, address book and task list functionality.
Privacy-focused, open-source email app offering encryption, unlimited accounts, customizable features, unified inbox, and low data usage.
Open source note-taking app with Markdown support, to-do integration, and synchronization with cloud services like Dropbox and OneDrive.
Open-source workspace with full data ownership, offline access, multi-platform support, and deep customization through themes, plugins, and templates.
Local-first, privacy-focused notebook supporting Markdown and Org mode, offline use, encrypted backup, extensible with plugins, and more.
An end-to-end encrypted note-taking by Proton. Offline access, unlimited sync across devices, tagging, passcode and biometric security, plus advanced premium privacy features.
Fully open-source, end-to-end encrypted notes with device-based security, secure sync, offline access, powerful editor, vault, backups, and exports.
A versatile open-source word processor with robust formatting, style options, and cross-platform availability, ideal for both memos and complex book publishing.
AbiWord is a free word processing program similar to Microsoft® Word. It is suitable for a wide variety of word processing tasks.
Words is an intuitive word processor and desktop publisher application. With it, you can create informative and attractive documents with pleasure and ease.
Impress is a truly outstanding tool for creating effective multimedia presentations. Does linear or non-linear presentations with the included Presenter Console extension. Your presentations can be enhanced with 2D and 3D clip art, special effects and transition styles...
Calligra Stage is an easy to use yet still flexible presentation application. You can easily create presentations containing a rich variety of elements, from graphics to text, from charts to images.
LibreOffice Calc is the spreadsheet program you've always needed. A fork of OpenOffice.org Calc, professional data miners and number crunchers will appreciate its comprehensive range of advanced functions.
The Gnumeric spreadsheet is part of the GNOME desktop environment: a project to create a free, user friendly desktop environment.
Calligra Sheets is a fully-featured calculation and spreadsheet tool. Use it to quickly create and calculate various business-related spreadsheets, such as income and expenditure, employee working hours, etc.
Draw lets you produce anything from a quick sketch to a complex plan, and gives you the means to communicate with graphics and diagrams. With a maximum page size of 300cm by 300cm, Draw is a an excellent package for producing technical drawings, general posters, and much else.
Base is a full-featured desktop database front end, designed to meet the needs of a broad array of users, for all kinds of usages, such as keeping track of collections of objects,maintaining customer information databases,maintaining student grade and curriculum...
DeepSeek is a state-of-the-art AI assistant designed to provide intelligent, conversational support across diverse tasks. It leverages advanced natural language processing and machine learning to answer questions, generate creative content, solve complex problems, and offer...
Privacy-first AI assistant with zero-access encryption, no logging or profiling, open-source code, and user-controlled conversations, subject to GDPR regulations.
Privacy-focused open-source chatbot running locally on consumer CPUs without GPU or internet, supporting multiple customizable large language models and licensing.
Open-source offline AI chat software supporting local LLMs, cloud model connections, custom assistant creation, OpenAI-compatible API, and broad hardware support.
Alpaca is an Ollama client where you can manage and chat with multiple models, Alpaca provides an easy and begginer friendly way of interacting with local AI.
LibreChat is a free, open source AI chat platform. This Web UI offers vast customization, supporting numerous AI providers, services, and integrations. Serves all AI Conversations in one place with a familiar interface, innovative enhancements, for as many users as you need.
Qwen.com is an interface to chat with Alibaba Qwen's Qwen series of models which are renowned for their huge context windows, generous free usage limits, reliability, and their continued tradition of being open-source.
Emphasizes privacy with end-to-end encryption, Proton Drive safely stores, synchronizes, and shares files across devices via web and mobile applications.
On-premises file sync, universal access, integrated collaboration, real-time communication with privacy and data control focus.
kDrive is a Swiss online storage service that respects its users' privacy and makes storing, sharing & collaborating on files a breeze.
Take your privacy to the next level with the secure Tuta Calendar app. This encrypted time-management tool is the most private way to organize your busy schedule – and it’s quick to navigate, comes with dark and light mode, plus, it’s perfectly integrated with the Tuta Mail app.
Snaps are software packages that are simple to create and install. They auto-update and are safe to run. And because they bundle their dependencies, they work on all major Linux systems without modification.
Utility for KDE's Plasma desktop environment for browsing, installing, and removing applications, implemented as an app store like application.
A software manager for the 
Linux Mint operating system to easily install new applications.
Comments
This list needs to be updated
To be fair, as soon as you make a list like this, it needs to be updated
An inspiring list, AxelFOSS! I moved away from Microsoft when they were forcing the move from Win 7 to 10! Faced a lot of challenges, ngl. But then no different from in MS ecosystem.
And because of my own experience, I do disagree with a lot of your choices. But looking at your list has inspired me to make one of my own. Thanks.
FOSS needs as many evangelists onboard as possible.
Just to tell you, I've had bad experiences installing LibreOffice and OpenOffice onto a mobile hard drive.
For Teams I would suggest:
Zulip , 
Mattermost and 
Infomaniak kChat