The best replacement for mhl is slimport.

The best alternatives to mhl are rated as following:
★★★★★  slimport
★★★★★  micro hdmi
★★★★  micro usb
★★★  miracast
★★★  mirrorlink
★★★  mini hdmi
★  mydp
  slim port
  allshare cast

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

Other search terms related to mhl and their ratings are:
★★★★★ usb otg
You have in mind a companion for mhl and it is not yet here? Propose!



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mhl
slimport
micro hdmi