If you're looking for larger scale syntax changes, you can look for modules that depend on Devel::Declare or on Filter::Simple. Not a complete list, but maybe a start.

Actually I'm looking forward to write some kind of tool for our team, which will help them deal with installing, configuring and upgrading syntax modules easily. Preferably some kind of easy GUI tool that helps them do it.

The team is really large and getting this kind of stuff installed on each and every system is a little difficult. Managing all the dependencies in absence of a standard is another problem.

Something like like one install taking care of all the defaults of the language, without having to worry about too much background complexity.

Actually I'm looking forward to write some kind of tool for our team, which will help them deal with installing, configuring and upgrading syntax modules easily.

As far as CPAN is concerned, syntax modules are just normal modules/distributions. So you can use the existing CPAN toolchain (like App::cpanminus, CPAN, CPANPLUS, CPAN::Mini) for that.

Managing all the dependencies in absence of a standard is another problem.

There is a standard for CPAN distributions: declare the dependencies in your build script, which then creates a META.yaml (or META.json); the standard toolchain can then be used to install all dependencies. You can reuse that mechanisms even if you don't write a module.

Perl 6 - links to (nearly) everything that is Perl 6.