I brought some camera batteries a couple of years ago from Duracell and they don't feel cheap or light but still working and no problems.
I remembered I phoned up to find out whether they make those battery themselves before deciding to buy them with questions about the weight of the actual battery. I got put through to someone (in England and not India which is good and inspires my confidence) and they who got back to be and said they buy them from a manufacturer called 2-Power.
I have a few universal car laptop power supplies from 2-power (with the automatic voltage set according to the tips) which work fine and seem to be well built. I brought a Greencell battery last year for someone from Amazon (not the thin lithium polymer type) and that seemed okay but the reviews seem pick and mix.
I was looking for a HP battery from a laptop that was only two years new and for some reason HP stopped making this particular battery despite still selling that model. I was recommended a supplier from but they seem to have different part numbers for their generic/third party batteries.
https://uk.eetgroup.com/