The best replacement for pen drive is flash drive.

The best alternatives to pen drive are rated as following:
★★★★★  flash drive
★★★  thumb drive
★★  hard disk
★★  external hard disk
★★  memory stick
★  memory card
  flash memory
  usb flash drive
  diskette
  jump drive
  usb drive

Your alternative for pen drive is not listed? Suggest!
Speaking about pen drive, one probably shouldn't forget about card reader.

Other search terms related to pen drive and their ratings are:
★★★★★ card reader
You have in mind a companion for pen drive and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of pen drive in all years. Click on graph for more.
pen drive
flash drive
thumb drive