Furnace not turning on, and can anyone identify these sensors?
I don't have enough rep to comment so I have to post as an answer.

With that said, I ran into this issue myself a few years ago, I cleaned off all of my sensors just like you did. This did not fix my issue so I went over my flame sensor with some fine grit sandpaper. (pic of flame sensor)
  

It has worked since I did this.

Question, when your tstat sends the heat signal, does your heater go through the motions like it will start up but shuts itself down after a few seconds? If so that's very indicative of a sensor issue. For future troubleshooting, basically all residential heaters (that I've seen) will have an LED indicator that will flash in a pattern representing the trouble code. Look up your make/model online and you can find what the trouble code means. Hope this helps. For full disclosure I'm a licensed electrician and not HVAC. Hope this helps.