Security in solidity - Ethereum has been always one of the most important topic. Some of the current most important tools are the followings:
SWC Registry /
Smart Contract Weakness Classification and Test Cases
Ethereum Smart Contract Security Best Practices
MythX - a cool tool for getting information on solidity smart contract vulnerabilities
EthLint - an open source tool for analyzing Ethereum smart contracts.
Slither - for making static code analysis on solidity contracts
Hydra - framework for security and bug bounties