Spark Plugs for Iridium? Never hear or it. But they seem to exit:
https://www.autozone.com/diy/spark-plugs/iridium-vs-platinum...
Platinum for Labware? Really? The world would look very different without Platinum or Platinum group metals. Start with the Oswald Process (Nitric acid, fertilizer), car catalysts, hydration of carbons, cracking, catalysts for a gazillion chemical reactions.