You might be interested to learn about the MMTk [1, 2] project which aspires to be a language agnostic library for garbage collection. It was used by the LXR authors [3] to develop a GC that beat production OpenJDK 11 collectors in throughput and latency. I believe they have work on a bunch of bindings to other VMs underway as well such as V8 (JavaScript), MRI (Ruby), Julia, GHC (Haskell), and PyPy (Python)!