There are gzip variants that break the file into blocks and run in parallel. They lose a couple of % by truncating the available history. But zopfli appears t

There are gzip variants that break the file into blocks and run in parallel. They lose a couple of % by truncating the available history. But zopfli appears to do a lot of backtracking to find the best permutations for matching runs that have several different solutions. There’s a couple of ways you could run those in parallel. Some with a lot of coordination overhead, others with a lot of redundant calculation.