Lightweight OSes/Windows XP alternatives

DeLi(cate) is a fork of DeLi Linux 0.8 targeted at very old and low RAM computers. It also works very efficiently on ordinary computers where you want to run lightweight applications and avoid the bulk of ordinary distributions.

Semplice Linux is a simple, fast and lightweight distribution based on Debian's unstable branch. It includes a small collection of up-to-date applications running on top of the Openbox window manager.

wattOS is a fast desktop Linux distribution based on Debian. Using the lightweight Openbox window manager as its default user interface, the distribution strives to be as energy-efficient as possible...

Slax is a minimalist desktop live CD based on Debian's "stable" branch, it boots into a simple desktop using the Fluxbox window manager which offers a small collection of applications.

Damn Small Linux is a very versatile 50MB mini desktop oriented Linux distribution.

Bodhi Linux, a lightweight distribution featuring the fast & fully customizable Moksha Desktop (https://alternativeto.net/software/moksha/about/). The 64-bit is built on top of Ubuntu (20.04). The 32-bit Non-PAE architecture has a Ubuntu 18.04 base – Bodhi Linux 6.0.

antiX is a fast, lightweight and easy to install systemd-free Linux live CD distribution based on Debian Stable for Intel-AMD x86 compatible systems.

Tiny Core Linux (TCL) is a minimal Linux operating system that manifests the Core Project's philosophy and focuses on providing a base system using BusyBox and flwm.

Linux Lite is a beginner-friendly Linux distribution based on Ubuntu LTS and featuring the Xfce desktop.

Peppermint OS is a user-friendly operating system that prioritizes mobility, efficiency, and ease of use, allowing users to quickly connect, communicate, and complete tasks without the need for extensive setup or customization.

Fast and powerful operating system based on the latest technologies while offering highly productive desktop environment. We focus on security, reliability, long-term stability and conservative integration of verified new features.

Trisquel is a computer operating system, a GNU + Linux distribution, derived from another distribution, Ubuntu, which is derived from Debian.

SliTaz is a free operating system, working completely in RAM and booting from removable media such as a CD-ROM or USB key. SliTaz is distributed as a LiveCD, and weighs less than 40MB. The system is quick and responsive, clean and robust.

MX Linux is an operating system - a cooperative venture between the antiX and former MEPIS communities. It is a midweight OS that combines an elegant and efficient desktop with simple configuration, high stability and solid performance.

Puppy Linux is a unique family of Linux distributions meant for the home-user computers. It was originally created by Barry Kauler in 2003.

Haiku is an open-source operating system that specifically targets personal computing. Inspired by the BeOS, Haiku is fast, simple to use, easy to learn and yet very powerful.

ReactOS™ is a FOSS effort to develop a quality operating system based on the architecture of Microsoft® Windows™ NT family of operating systems, that is compatible with applications and drivers written for it (NT4, 2000, XP, 2003, Vista, 7).