The mods in the pack including detailed versions are here: https://demosthenes.org/Minecraft/SadZombieLand/dist/SadZombieLand.xml
This pack has been thru a few playthroughs over 2 years, so these versions seem stable and functional.
If you are interested in cobbling together your own pack. Remember Greg provides default configs for other mods to make them work with GT6.