Sklansky-Chubukov did the work to make a chart of these. The idea behind the chart was that you could profitably shove your stack from the small-blind into the big-blind, even if you shoved and then immediately turned your hand over. That means your opponent would call if it was profitable for them, and fold when it wasn't.
Also, the worst hand 32o has 32.3% equity against a 100% range. It's 28.38% against the top 20% of
hands. Even against AA it is 12.79%. That means if you are being offered 6.8-1, you can't really fold even if you hold 32o. But, since people shove wider than that, when short, you really can't fold it for 2.5-1.
As an example, let's get ridiculous:
$0.50/$1 game 10-handed. You have $2. The whole table calls $1, and the SB shoves for $10,000. Everyone else mucks out of turn. So, it will be heads up with you against the SB. There is $11 out there, and you have to call $1 to be all-in. Can you find a hand that it wouldn't be profitable to call with? You only need 8.33% to break even here. The only example I can think of is something like K3o after the SB shows you KK. Although, if he could have AA or KK, you call with K3o.
Edit: AA vs 7-2o is 88.2:11.8, so if you have 7.5-1 direct
odds, it's a call. These spots don't normally come up, except in weird tournament spots. Sometimes a person is very crippled and they raise all-in into your big blind for much less than even a min-bet. That's just an autocall spot, even if you don't look at your cards.