The "Capture the Ether" project is an interactive game in which you hack Smart Contracts to learn about security.
The different categories you work through will educate you about important topics such as integer overflows and underflows or ownership rules. Every challenge has points attached to it. The more points you get, the harder the challenge.

Wargame in which you hack Ethereum Smart Contracts to learn about security best practices.

Capture the Ether

The "Cipher Shastra" project is an effort to help you sharpen your security skills by solving CTF-like challenges from the fields of Blockchain Security, Smart Contract Exploitation and Cryptography.
Protip: Some of the challenges have writeups listed at the bottom of the page you can use if you ever get stuck.

CTF challenges to learn about Smart Contract security.

Cipher Shastra

During the "DeFi Summer of 2020" there was a period of time where new Smart Contract exploits were reported on an almost daily basis.
If you want to learn how the infamous DeFi hacks worked and how you can take out a Flash Loan to manipulate Oracle price feeds you should definitely check out "Damn Vulnerable DeFi".
Protip: If you get stuck, not making any significant progress you should check out the <a href="https://forum.openzeppelin.com/">OpenZeppelin Forum</a> where community members share and discuss their solutions.

Wargame to learn how infamous DeFi hacks were conducted.

Damn Vulnerable DeFi

DeFi Hack is a CTF / Wargame focused on popular DeFi exploits and vulnerabilities. It's based on The Etherneut wargame by the OpenZeppelin team.

CTF / Wargame focused on popular DeFi Exploits and Vulnerabilities.

DeFi Hack

"EtherHack" is CTF / Wargame in which your goal it is to break into various Smart Contracts written in the Solidity programming language.
There are 6 level in total you can work through. The difficulty increases every time you reach the next level.

CTF / Wargame to learn about Smart Contract security.

Etherhack

"The Ethernaut" is an interactive wargame in which you switch roles and step into the shoes of an attacker to exploit Ethereum Smart Contracts.
In order to play The Ethernaut you should be proficient in Solidity and Web3.js. It's levels are sorted in ascending order (Easy - Hard), so you want to start with Level 0 and work your way up from there.

Interactive wargame that teaches you Ethereum Virtual Machine (EVM) security fundamentals.

The Ethernaut

The "Paradigm CTF" is an Ethereum-focused security competition organized by the crypto asset investment firm Paradigm. When participating one needs to solve CTF-like challenges focused on EVM- and Smart Contract security.
Protip: Paradigm usually shares solutions in the form of a GitHub repository once the competition is over.

Ethereum-focused CTF-style security competition.

Paradigm CTF

"Security Innovation Blockchain CTF" is a dApp which is built based on vulnerable Smart Contracts the contestant has to exploit.
The different levels are modeled based on real-life use cases, ranging from lotteries to ICOs to automated royalty agreements.

CTF dApp built based on vulnerable Smart Contracts to exploit.

Security Innovation Blockchain CTF

Buildspace is an effort to teach you fundamental Blockchain- and Web3 concepts through project-based learning.
Once joined you'll have access to courses that'll show you how to build EVM-based dApps with Solidity, generate an NFT art collection or implement a Blockchain game based on L2 networks.

Online courses to learn about Blockchain- and Web3 Technologies.

Buildspace

Figment Learn is a platform created by developers, for developers to learn about Blockchain and Web3 technologies.
Browsing through it you can find resources to learn about various protocols, courses to study a topic in a guided setting, as well as curated community tutorials to dive deeper and apply what you've learned through example projects.

Platform for developers to learn about Web3 Technologies.

Figmet Learn

RabbitHole is an educational project that lets users earn crypto by using the latest decentralized apps (dApps).
Once the user's wallet is connected one can work through different quests, learn specific skills and explore new projects.

Learn how to use and contribute to dApps.

RabbitHole

In "CryptoZombies" you'll learn Solidity, one of EVMs programming languages by building an NFT game in which you create, train and grow an army of Zombies.
Given its playful nature it's one of the best best introductions to the EVM and Solidity. While definitely interesting you might want to focus on the first two mini-courses and skip the "Beyond Ethereum" one when starting out.

Learn Solidity and dApp development by building a Zombie game.

Code challenge