The best replacement for potassium iodide is iodine.

The best alternatives to potassium iodide are rated as following:
★★★★★  iodine
★★★★  potassium iodate
★★  potassium
★★  iodate
★★  kelp
★  sodium iodide
★  iodine from kelp
★  nascent iodine
★  potassium gluconate
★  potassium chloride
  potassium citrate
  potassium iodide
  ammonium iodide
  potassium iodine
  sea kelp

Your alternative for potassium iodide is not listed? Suggest!
Speaking about potassium iodide, one probably shouldn't forget about lead nitrate.

Other search terms related to potassium iodide and their ratings are:

★★★★★ lead nitrate
★★★★★ silver nitrate
★★★★ chlorine
★★★★ hydrogen peroxide
★★★ iodine
★★★ lead (ii) nitrate
★★ potassium iodate
★★ chlorine water
★★ copper sulfate
★★ hydrogen peroxide equation
concentrated sulphuric acid
bromine water
chlorine gas
sodium thiosulphate
You have in mind a companion for potassium iodide and it is not yet here? Propose!

Google Trends

Scale is based on the average worldwide traffic of potassium iodide in all years. Click on graph for more.
potassium iodide
potassium iodate