In addition to the SmartPy manual, here are some guides that allow you to learn more about various topics:
Tutorial: A step-by-step introduction to SmartPy.
Tokens: A quick overview of token standards on Tezos and their implementations.
FA2 lib: A library for implementing smart contracts for digital assets (fungible tokens or NFTs) using the FA2 token standard.
Examples: A list of example smart contracts with documentation.