I use Racket which comes with a ton of features that let me build larger systems. Other more pure Scheme systems like Guile also have the capabilities to build

I use Racket which comes with a ton of features that let me build larger systems. Other more pure Scheme systems like Guile also have the capabilities to build modules/libraries, etc... and there is a decent amount of code out there to do stuff. You do have less of a choice for certain things than languages like Perl or Python, but most modern Schemes or Scheme-like languages are pretty good.