We're planning to write proper documentation soon.
Which languages are most interesting to you? We wrote the client with an eye towards supporting R and Scala. A PR or FR on GitHub would be ideal. We also have a Slack channel where we can support you if you want to tackle adding language bindings to Quilt. feedback at quiltdata dot io.
Ruby and Go, personally.
The package metadata is stored in JSON so that should be pretty easy to access in either Ruby or Go. Tabular data is stored in Parquet by default. Do you know of any good libraries for reading and writing Parquet in Ruby and Go? Do either of those languages have a DataFrame-like class/struct?