I'm going to plug my own here: astpath, which is AST-based search for Python. https://github.com/hchasestevens/astpath/

Yes, https://github.com/mvdan/gogrep for Go

I've found a few, eg https://www.graspjs.com/ is a Javascript one.

I do wonder if there is a multi-language aware one though.

googling returned https://github.com/azz/ast-grep for js