A Gramex extension is available on Visual Studio. It features snippets for Gramex.
In Activity Bar under Extensions tab search for Gramex Snippets. Alternatively, you can find the extension on VSCode Marketplace.
In gramex.yaml or any .yaml file, type grx-form… It prompts FormHandler related snippets as suggestions.
There is an auto-suggestion bug in VSCode for YAML snippets. To work around this go to Preferences -> Open Settings (JSON) and add:
"editor.quickSuggestions": {
"other": true,
"comments": false,
"strings": true
}

Features will be updated rapidly, visit the VSCode Marketplace to get the latest feature list.