This mod adds a gamerule to change the push limit of pistons.
It just affects the server side, so clients don't need to have it installed to join a server that uses it.
How to install
To install the mod, first you need Fabric. You can get it from https://fabricmc.net/use/.
Then just drag the downloaded jar file to %appdata%\.minecraft\mods.
How to use
To change the limit, type in:
/gamerule pistonPushLimit <limit>
If you set it to -1, the mod will remove the limit altogether. This could cause lag or even crash Minecraft, so use it with caution.
Why would you want to change the limit?
The possibilities are endless, especially when using slime or honey blocks. You can build huge flying machines without having to take into account the annoying 12 block limit.
PhoenixSC tried out this modification a while ago and showed a few crazy contraptions: https://www.youtube.com/watch?v=aGWFPnlzFmA
Demonstration: https://www.dropbox.com/s/e9rta9e4y0xum0l/NoPistonLimit.mp4