There are still challenges with basics like compression, which tends to involve trawling Github for the least dubious toy project. Even Apple's Compression framework is missing important algorithms like ZSTD.

Another problem is the Apache Software Foundation don't seem to have any Swift maintainers, which means there really aren't any good pure Swift libraries for Arrow or Parquet.

There are some really good open-source libraries from Apple like Swift Collections or Swift Binary Parsing.

A good source of available packages is the Swift Package Index. You can search here packages compatible with Linux[0].

[0] https://swiftpackageindex.com/search?query=platform%3Alinux

As of very recently, the entire stdlib (i.e. "Foundation") is open source and available on all platforms Swift targets. For a while, the Linux builds had a much smaller/limited version of Foundation, but it's fully supported now.