I recently switched from Sublime Text to VSCode and created a plugin for the textmate language grammar for journal files (.ledger and .ldg). I'm still maintaining the sublime syntax file, too. All the things are here:
The rules are targeted at standard account roots: expenses, assets, liabilities, income, and equity. (Or one letter aliases of same, except for equity.)
I think it looks nice and colorful:

In Sublime Text, I originally used scopes that had these colors with a Monokai Dark theme, but there are settings included in repo for both ST3 and vscode to match what is shown here and in the syntax readme.
It handles tags, balance assertions, balance assignments, and virtual postings. I don't use a lot of ledger features and make no promises on how it does for more complicated journal files, but I'd be open to attempting updates if given examples.