to think cookware for single people just doesn't exist?

I have given away several of my larger saucepans and bits of ovenware but no, I don't find it a problem at all.

Also, look on Vinted, OP. There are some really good value Staubs on there, as well as some of the other suggested pots, in good condition.

Not sure where you live but Staub/Zwilling have shops for B rated stock at discounted prices in Bicester Village and Wembley. You can also shop via WhatsApp from these shops and they will ship to you. You can also find them on Amazon Warehouse at discounted prices. Huge Staub fan, you won’t regret your purchases even if you buy at full price and if you look after them well they will last you for life.

Glass/pyrex cookware is a good option though - good value and comes in lots of different sizes with lids. just brown the ingredients in a frying pan on the hob and tip in.

Wilko might be helpful here - I found some smaller cookware for my mum on their website recently - https://www.wilko.com/en-uk/my-grey-casserole-dish/p/8291628
I also found a slow cooker for my BF when he is on his own - amzn.eu/d/031mxw1y

I simply cannot imagine a planet on which I would ever cook only enough rice for one serving.

As a pp commented, it’s not ‘leftovers’ - it’s just normal, sensible cooking.

You might want to try searching under ramekin as those are single serving oven proof dishes. I do single serving shepherds pies in them

https://www.johnlewis.com/browse/home-garden/cooking-baking/view-all-roasting/ramekins/_/N-7d9wZ1z0p3yl

they are miniature casserole dishes.

The smallest Le Creuset casserole (cast iron) is only 1.5/1.7 litres I think, and it's the one I use the most since my husband died. But the smallest stainless steel saucepan is even smaller - not sure of exact size, and it has a metal handle and lid so is also perfectly oven proof as well.

I have never had an issue, but I agree with the OP - I don't like batch cooking, because I almost never fancy the same thing two days in a row. Once it's been frozen I go right off it anyway! Freshly cooked from fresh ingredients is almost always better, if cooked properly. The reason that bolognese / casseroles / etc often taste better second timer round is that they were never cooked long / slow enough in the first place, IMO :)

You can still cook a smaller meal using larger items, you just cook as much as you need. I've never came across this being a problem tbh

You can get 550ml or 1l fairly easily. Is there a reason why those won’t work?

700ml is a funny size because it would need a tiny diameter, which is inefficient on an induction hob where the smallest ring is going to be too wide for it, its not like a gas burner where you can cook on a really small flame. Its easy to find 1L options which should be fine.

Buy Staub La Cocotte Cocotte | ZWILLING.COM 800ml

And Staub's superb, much prefer it to Le Creuset.

Don't have any issues finding cookware that works size wise, but get very annoyed at vegetable portions. I dream of being able to buy individual small lettuces, or a sensible portion of spinach.

Pan version as well, loads of other shapes on the website. Not cheap but you buy once and use them for life: https://www.zwilling.com/uk/staub-pans-16-cm-cast-iron-frying-pan-graphite-grey-40501-145-0/40501-145-0.html?cgid=cookware_skillets-fry-pans

https://www.zwilling.com/uk/staub-la-cocotte-12-cm-round-cast-iron-rice-cocotte-graphite-grey-40509-702-0/40509-702-0.html?kb=ga_shp_23006790896_183020099737&gad_source=1&gad_campaignid=23006790896&gclid=CjwKCAiAqprNBhB6EiwAMe3yhoBT4CE-O-CZAiYz434w8jECfNWIQtf2YeSsdmdCleNYii9m1ErC4xoCGEsQAvD_BwE

Also single but generally cook 2-3 portions and take to work for lunch or eat the next day. I suppose as I buy eg meat in large packets as it’s cheaper (and you can’t buy v small amounts unless you go to a butcher) then to me it makes sense, food is still fresh and it is definitely cheaper. There’s some stuff I cook fresh each time if I can though, like veg and roast potatoes. Other stuff like chillis or curries usually taste better next day I think.

You can get mini slow cookers (1-1.5L) that would work for smaller portions. It is more about diameter I suppose. Same as pans - I use 14-16cm pans a lot.

I also use my instant pot quite a bit. If I’m cooking several portions I just use the pot but you can do ‘pot in pot’ cooking - ie put a small pot/pan in the instant pot on the rack and cook individual portions that way. Might be worth checking out as you could get pie dishes to use make individual portions.

This rice cooker is amazing: can do 1-2 (even 3 small) portions with no faff. www.lakeland.co.uk/62569/lakeland-mini-electric-rice-cooker-05l

Just get a small cast iron frying pan and a lid, there are tons of them.

Honestly it sounds like you want something super specific and it just happens to have a limited audience.
You can get plenty of small size pans and glass oven dishes for casseroles/lasagne/individual pies etc but what’s maybe less easy is a pan you can cook in on a hob & then transfer into the oven in that sort of size. As many have said that’s likely as it’s used for the type of food the majority would cook a bigger portion of and have some leftovers. You then also want it to be suitable for an induction hob

Ultimately lots of people don’t have induction hobs so won’t care about that bit, lots of people like to batch cook &/or have families so won’t have the interest in a small casserole pan, lots of people wouldn’t bother to cook something like a casserole from scratch for one and instead buy something pre made or eat out. There are probably limited options because there is a limited demand but hopefully one of the links shared will work for you.

How amazing, ChatGPT can’t find anything yet actual people can find options in minutes.

I'm on my own and cook everything from scratch. I've never had a problem with finding suitable pots and pans. And it doesn't really matter if a pot or dish is too big anyway.

I searched amazon for small 1 litre cookware. Not induction suitable but oven suitable

Have you tried going to IKEA instead of (sigh) "asking" chatGPT?

I spent over a decade living alone, I've literally never ever had this problem.