Sharing something I've been working on lately: an AWS IAM Language Server (and VSCode extension). Use it with any editor that supports LSP
It can emit diagnostics for invalid actions, messed up regions/account ids, duplicate sids, etc. It also gives you completion for actions, arns, condition operators, context keys, etc
It also supports policies defined in any YAML, JSON, or Terraform/OpenTofu file, at any nested level, so your policies defined within a CloudFormation resource will be picked up
Check out the repo for more, feel free to open an issue if you have issues: https://github.com/mbarneyjr/aws-iam-language-server
If you use vscode you can get the extension here: https://marketplace.visualstudio.com/items?itemName=MichaelB...
Demo video: https://x.com/mbarneyjr/status/2039329871843729809
