The WiredTiger storage engine supports several compression engines that are not exposed via MongoDB. It would be interesting to know whether there is value in exposing additional compression engines - it would also be very valuable to create a test that could be used to measure the relative compression rate vs CPU usage characteristics of different compression engines for a few interesting MongoDB workloads.

The particular compression engines that might be interesting are LZ4 and zstandard. A full set of compression libraries supported by the WiredTiger team is here:
https://github.com/wiredtiger/wiredtiger/tree/master/ext/compressors