In addition to the good suggestions here check commercial restaurant kitchen equipment suppliers. There are plenty of things to contact a blacksmith about but a pot isn't one of them in my mind.... maybe if you want a hand hammered cauldron but.... it is going to be vastly cheaper to find something commercially available ESPECIALLY with stainless steel... I don't know any blacksmiths working with stainless steel. I dunno how I got on about stainless steel... magnetism is an easy way to roughly check grades of stainless... what you want depends on your requirements

162 qt pot - https://www.ontariobeerkegs.com/bayou-162qt-stock-basket.html

Torontonians need not limit themselves in potential; they simply require belief and steely resolve

Tap Phong in downtown Toronto may not have them on their website but if you called they would have better idea of what they have on their shelves.

Home brewing equipment comes in sizes up to ~80L that plug into normal household power, and any size bigger than that on less normal power. Similar size stuff can be pretty easily gotten anywhere designed to be heated externally.

Do you need a pot designed to be filled with a 5kW pump and whose top is reached by ladder?

You need to contact a catering supply company, ie for restaurants and such, here's one a 2 minute Google found:

https://www.canadafoodequipment.com/product/thermalloy-s-s-deep-stock-pot-100-qt-lid-5724150/

100qt is about 115l

50 gallon drum for Mr. Dahmer over here

What are you poutine on?

Lots of restaurant supply stores in that city. You’ll have to go in person but you’ll find big ones there.

I'm not familiar with Canadian law, but I think people from Toronto are allowed to buy pots just as big as the rest of us can.

I'm not a lawyer, though.

What are you up to, bro?

A cybertruck?

My first thought would be a kitchen supply store like a WholeSale club, if there's one in Toronto. I bet you could probably order larger pots direct from the manufacturer of said pots too.

AFAIK steel quality is more about use case then any type that is best overall; so, I would think all pots are made out of the same type of steel and it isn't something you should be worried about. That being said, anything made of steel could last a lifetime if you take care of it and avoid throwing it into a volcano.

There's lists out there that ...list each types proclivities or at least there were before ai fucked everything. Some types are more resistant to corrosion then others but softer, some more brittle but keep an edge longer, etc.

Is it this?

https://www.whiting.ca/equipment-divisions/metallurgical-equipment/charge-buckets/

Just two cents:
In the us the biggest pots I've seen for cooking - they were always at an Asian supermarket. Some of them were enormous woks, but they had big cookpots also.
I would also look into camp fire pots, that you have to hang from a tall tripod - those can be really big also.

I’m sure you have a local blacksmith who accepts commissions, so… really, really big?

We only allow people from Toronto to buy ceramic pots due to the reason

Does it need to be forged in one piece? Because if you are fine with it being welded together, the limit is based on how high of a scaffolding we can build. I guess you can go as high (and the height also as width, assuming you want a standard shaped pot) as the Burja Khalifa (or however that was written). But it may be quite expensive.