"Getting Started with Qiskit" https://qiskit.org/documentation/getting_started.html
Qiskit / qiskit-community-tutorials > "1 Hello, Quantum World with Qiskit" https://github.com/Qiskit/qiskit-community-tutorials#1-hello-quantum-world-with-qiskit
"Quantum basics with Q#" https://docs.microsoft.com/en-us/quantum/quickstart?tabs=tabid-python
Qutip notebooks: https://github.com/qutip/qutip#run-notebooks-online
Jupyter Notebooks labeled quantum-computing: https://github.com/topics/quantum-computing?l=jupyter+notebook