All of them; although technically, given their greater mass and resistance to yielding to said toe, a standard would be worse than a portable. Typewriter cases (with machines) would fall in between. Empty cases would be the best scenario for avoiding injury.

Stubbing toes is all fine and good, but I would up the ante and include ramming a lower shin against the edge of a ledger size carriage. Since your foot would clear the underside of such a carriage it would be your shin that would have to take the full impact.

And there's something else to consider: the off-balance trip and fall. If you've ever navigated a minefield of typewriters you'll know what I'm talking about. There's nothing worse than carefully tip-toeing through a crop of machines and in the process catch a heel on one just as you're leaning to place that step.

Uwe wrote:

All of them; although technically, given their greater mass and resistance to yielding to said toe, a standard would be worse than a portable. Typewriter cases (with machines) would fall in between. Empty cases would be the best scenario for avoiding injury.

Stubbing toes is all fine and good, but I would up the ante and include ramming a lower shin against the edge of a ledger size carriage. Since your foot would clear the underside of such a carriage it would be your shin that would have to take the full impact.

And there's something else to consider: the off-balance trip and fall. If you've ever navigated a minefield of typewriters you'll know what I'm talking about. There's nothing worse than carefully tip-toeing through a crop of machines and in the process catch a heel on one just as you're leaning to place that step.

I can say a resounding, "Hear, Hear!!"  You should see my garage.  I have for years navigated over said minefields, and yes, I've landed butt-first onto a few machines.  What's the worst typewriter to stub your toe on?  I'd have to say any heavy upright manual or electric placed on the floor.
 

The worst of all for me: Optima M14.

Tank-sized, tank-like armour plating, tank-ish tonnage and lots of sharp edges and corners.

The aforementioned minefield stopped being a problem for me when I relocated the typewriters from the basement to the top floor. Down there the problem was that the minefield was so dense that I could not walk past it!

Most likely not his heart. I can't recall Hemingway ever being described as a bleeding heart...

All right, now let's hear from those who repair typewriters who have stories to tell about cuts, bruises, burns (from electric machines), and various and sundry other unfortunate occupational hazards accompanying typewriter repair.  I'll start first:  Summer, 1983:  1948 Royal KMM--run over left thumb on toothed carriage rail--scraped the hide off the end & had to wear bandage for 2 weeks;  Spring, 1984:  1958 Underwood Golden Touch--sliced right index finger trying to keep spring drum from spinning as I was putting on the drawband, but spring drum ran away and spun over my finger as it was between it and the rear carriage rail;  Spring, 1985:  193x IBM Electric--burned left thumb and index finger on ceramic resistor in back of machine trying to get a bolt out from the bottom;  Most other injuries involve cuts from slipped screwdrivers.  Two injuries, no recall of when these occurred, the typewriter fell on my feet, scraping my shins and bruising my metatarsals.  Spring, 2016:  1955 Underwood 150--unsticking keys by pushing upward on key levers--developed cut in my left index finger.  Used rag to do this after injury.