Rust

Learning Rust with Too Many Linked Lists is the best first stop. It implements several linked lists and uses each one to explain ownership, borrowing, Box, Rc and unsafe code, which are the parts of Rust that confuse most newcomers. hecto: Build your own text editor in Rust, by Philipp Flenker, adapts the kilo editor tutorial to Rust and is a good first complete program.

For systems work, Philipp Oppermann's Writing an OS in Rust blog builds a small x86-64 kernel with no standard library, covering booting, VGA text output, interrupts, paging, heap allocation and async tasks. Writing NES Emulator in Rust is a free online book that emulates the 6502 CPU, the PPU and input, and Matt Brubeck's Build a browser engine in Rust builds robinson, a toy engine that parses HTML and CSS and lays out boxes.

Web and app projects include A Simple Web App in Rust (3 parts), Write a Microservice in Rust, Single Page Applications using Rust with Yew and WebAssembly, and Rust in Detail: Writing Scalable Chat Service from Scratch (2 parts). Learning to Fly (4 parts) simulates evolution with a neural network and a genetic algorithm and compiles it to WebAssembly, and there is a roguelike that runs on the desktop and the web. Some older posts predate Rust 2018 and async/await, so expect compiler changes.