All groceries. It might be a surprise to some, but generic brands are usually very good in this area. My approach is to always buy the generic first, and if it's not good enough then try a name-brand.

Certain OTC meds for me, the generics are identical to the name brand

Anything that's basically one ingredient or one active ingredient. If you're buying ibuprofen, for instance, there's zero reason to buy the name brand (Advil) vs the store brand.

Past that, there are some store brands that are actually a big brand. The big brands do that so they can get the bigger margin selling as a name brand, but more volume selling as generic. Costco is and example of that - many Kirkland products are made by major brands.

Kirkland premium vanilla ice cream.

Store brand is good depending on the store. For example, Costco or HEB (in Texas) have store brand products that are equal and sometimes better in quality than their branded counterparts. So when I’m at a store like that, I look for the store brand version first when buying an item.

Distilled water

Anything Aldi brand, Wal-Mart store brand is the same price usually, but Aldi just seems to have better quality. Really it's easier for me to list what I won't ever buy store brand: toilet paper, laundry detergent, and hot sauce.

Most Costco-brand things are pretty decent. We can't get their liquor where I live, though.

Pretty much everything I consume. The main exceptions are canned tomatoes (the store brands are always sourer than I'd like), some cheeses. I used to also buy brand pasta, but ever since my supermarket got its own generic bronze-cut pasta I no longer need to.

When it comes to medicinal products I'm more likely to get a brand version though, e.g when the brand version works better, like with Tiger Balm, or when a generic isn't available.

Everything except a very small number of products. eg. The store brand equivalents of total cereal are cheaper because theyre not as fortified. That is important for people that actually want that extra nutrition eg. women, people with anemia, vegans, anyone that drinks a significant amount of alcohol etc. Ranch used to be one of the things that I regretted getting the store brand (the store brand was NASTY) but luckily that hasnt been true for a while. Most medicines are just fine as generics as well and the ones that arent will generally be specifically requested by your doctor.

Half n Half just now. Kroger brand. 2.50 is plenty for this little thing of half and half

Aldi’s Clancy’s chips. Name brand are just too greasy for me. Also, I just tried their garlic bread chips and those are dangerous.