The best replacement for displayport is dvi.

The best alternatives to displayport are rated as following:
★★★★★  dvi
★★★★  hdmi
★★★  mini displayport
★★★  vga
★★★  thunderbolt
★★  dvi-d
★★  mini dvi
★  dual link dvi
★  dvi dual link
★  dvi quality
★  displayport
★  hdmi 2.0
★  dual dvi
  vga better
  hdmi port
  displayport 1.2
  dvi better
  mini-displayport
  dvi port
  displaylink
  dvi-d dual link

Your alternative for displayport is not listed? Suggest!
Speaking about displayport, one probably shouldn't forget about multiple monitors.

Other search terms related to displayport and their ratings are:
★★★★★ multiple monitors
★ displayport cable
★ thunderbolt display
You have in mind a companion for displayport and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of displayport in all years. Click on graph for more.
displayport
dvi
hdmi