What do people do with incandescent light bulbs ?

Nearly all of the energy they use is converted to heat. I wish I still had a 100W bulb or a couple of 60W ones; I would then be able to repurpose them as a heat source, converting the little computer desk at which I’m currently sitting into a mesa camilla. It just needs a big blanket over it reaching to the floor and a suitable heat source, guaranteed to keep me toasty at least from the waist down. I reckon a securely mounted and shaded bulb or two would do the trick, and probably be less risky than the arrangements I remember from my childhood in Spain:
 

​With his volunteer firefighter’s hat on I suspect that ​@Blastoise186  won’t like that heath robinson looking fire hazzard at all.

That looks like a wood fire in a cage with blankets draped over it.
A lightbulb would be slightly better, but still a hazzard if the blankets were to get in contact with it.

However ​@Firedog  has reminded me of the ‘Flying Saucer’ bed warmers that we had as children.

They were just a 40w incandescent bulb in a metal housing, they warmed a bed nicely

https://www.objectlessons.org/houses-and-homes-20th-century-to-present/belling-bedwarmer-1960s-original/s60/a998/

You could get similar, but different shaped, lightbulb heaters for use in greenhouses, garages, etc.

Haha, true! But at the same time it’d be my colleagues that’d have to pull you out of the house, not me! :P

But yeah… I’m not keen on that lightbulb blanket combo somehow… I couldn’t possibly tell you why… Oh wait, I can!

In the spirit of never throwing anything away I have a 200 W light bulb amongst the hoard, and a couple of 150 W too from my mother in law’s !! I could post them to you Firedog and you could start a cottage industry…!! 
One bonus of your idea is you would know it was switched on 💡

I think if incandescent bulbs were prone to exploding, they would have been banned decades earlier (and I think you’d notice if one had). Lightbulb heaters like Nukecad refers to could come in very handy, e.g. equipped with a timer to keep a wardrobe aired and must-free. My 100W towel rail doesn’t manage to get my bathroom warm enough to protect me from hypothermia when I eventually pluck up the courage to go for my shower, but another 100W or two might. 

They are only e-waste if they’re used wastefully. As heat sources as and when appropriate, there’s no energy wasted.

Then of course there’s the box full of fluorescent energy saving bulbs which I’ve replaced with the LED ones… 🤦‍♀️

​@Firedog back in the 60's/70's we had an ingra-red ‘heat and light” bulb in the bathroom which was pretty good and lasted years.

You can still buy them, don't know how good they are now.