Gotta Go Fast
Very simple Core Mod for 1.12
This mod removes the server side check for if a player moves too far too quickly which then teleports them back. Allows clients to send fast update packets. Beware.
This allows people to travel faster with things like the IC2 Jetpack.
Just drop it into your server's mods folder and enjoy the freedom. (No harm having it on client, but is not necessary)