Forge mod.

Uninstalling older versions of this mod and using it on a world that previously had it installed may have negative consequences!

Bigger stacks

Allows you to increase stack size beyond 64, up to ~1 billion (though I don't recommend you go that high).

Control the stack size of individual items

The mod allows you to change the stack size of items based on tags, what mod it comes from, and more using rules.

Quickstart

When you load into a world with the mod unconfigured, it will show you this prompt:

Clicking on the command or running it will open a configuration GUI. 

You can open this GUI at any time by running /biggerstacks quicksetup

Compatibility

With a mod like this, it is very likely that some things will be incompatible. If you find any issues, or things not working as expected, report them on github.

Some item transport mod (xnet, modular routers, pretty pipes, cyclic) have been changed for bigger stacks. There is some more information about the changes in the config file.

Please report any issues/incompatibilities you find with this mod to me, not the author of the other mod.

You can report them on the github issues or the comments section here, though I'd prefer you to use the github issue tracker if you have a github account.

Known incompatibilities 

- numismatic overhaul reforged

Client side and server side?

This mod is needed on both the client and the server.

Also on curseforge

Forge mod.

Uninstalling older versions of this mod and using it on a world that previously had it installed may have negative consequences!

Bigger stacks

Allows you to increase stack size beyond 64, up to ~1 billion (though I don't recommend you go that high).

Control the stack size of individual items

The mod allows you to change the stack size of items based on tags, what mod it comes from, and more using rules.

Quickstart

When you load into a world with the mod unconfigured, it will show you this prompt:

Clicking on the command or running it will open a configuration GUI.

You can open this GUI at any time by running /biggerstacks quicksetup

Compatibility

With a mod like this, it is very likely that some things will be incompatible. If you find any issues, or things not working as expected, report them on codeberg.

Some item transport mod (xnet, modular routers, pretty pipes, cyclic) have been changed for bigger stacks. There is some more information about the changes in the config file.

Please report any issues/incompatibilities you find with this mod to me, not the author of the other mod.

1.12?

There are very similar mods for 1.12 already available