The best replacement for folders is binders.

The best alternatives to folders are rated as following:
★★★★★  binders
★★★★  files
★★★★  tags
★★★  metadata
★★  directories
★★  labels
★★  collections
★★  briefcase
★  sharepoint
★  libraries windows 7
★  metadata sharepoint 2010
★  subdomains
★  collections lightroom
★  tagging
★  categories
★  categories outlook
★  mailboxes
★  metadata sharepoint 2013
★  document sets
★  scrunchers
★  unrecognized files
  archive folders
  metadata sharepoint
  albums
  personal folders
  libraries
  views sharepoint
  contexts

Your alternative for folders is not listed? Suggest!
Speaking about folders, one probably shouldn't forget about prongs.

Other search terms related to folders and their ratings are:
★★★★★ prongs
★★★★ dividers
★ .svn
You have in mind a companion for folders and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of folders in all years. Click on graph for more.
folders
binders
files