The best replacement for sd card is sdhc card.

The best alternatives to sd card are rated as following:
★★★★★  sdhc card
★★★★★  sdhc
★★★★  compact flash
★★★  memory stick
★★★  usb
★★★  cf card
★★★  flash drive
★★  sim card
★★  micro sd card
★★  xd card
★  sd card
★  usb flash drive
★  mmc card
★  mmc
★  memory card
★  ssd speed
★  usb faster
★  micro sdhc card
★  internal memory
★  thumb drive
★  mini sd card
★  external sd card
  compact flash card
  usb drive
  sdxc
  micro sdhc
  microsd
  internal storage
  multimedia card
  cf
  xd
  usb stick faster
  usb speed
  phone memory
  class 10
  usb drive faster
  memory stick duo
  usb flash
  hd card
  emmc
  expresscard 34 slot
  multimedia
  class 4 sd
  pro duo
  tf card
  stick
  flashdrive

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

Other search terms related to sd card and their ratings are:
★★★★★ usb
★★ arduino
★ rooting
★ root
readyboost
ready boost
homebrew
You have in mind a companion for sd card and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of sd card in all years. Click on graph for more.
sd card
sdhc card
sdhc