Everything here touches Salesforce in some way, which makes this the widest tag on the blog rather than the most useful one. If you are after something specific, the narrower tags will get you there faster: contract management for CLM and agreement workflows, integrations for connecting Salesforce to the systems around it, and developer tools for the build side.
A free, open-source VS Code extension for Salesforce developers: org-aware Apex and SOQL autocomplete, an Apex/SOQL/logs workbench, a data migration wizard with revert, a REST explorer, Apex test coverage in the gutter, and a process visualizer that shows what actually runs on a record change.
Salesforce development means juggling IntelliSense, debug logs, deployments, package management and API testing across separate tools. ASFX Toolkit pulls them into the editor. It is free, open source, and driven by the Salesforce CLI you already have.