Thank you notes after funeral

[Maremaremare]

We had my mother's funeral recently and my Aunt mentioned that we need to write thank you notes. Is this still the done thing? Do I write them just to those who attended the funeral, or those who sent cards as well? Or just to thank those (that I know of) who donated money, to a hospice?

Advice appreciated!

Seems a done thing in the Netherlands. A friend has a box from the printer as part of the funeral announcement card package.
We didn't do them afte FIL's funeral but MIL is a bit of a rebel with social convention.

We didn't. I haven't heard of this either.
You have enough to be getting on with.

Sorry for your loss.

Loads of people attended our family funerals - there is no way we had the emotional energy to send thank you letters or cards to those who attended

Beyond family and a few others, I couldn't even tell you who was at my mum's funeral.

And my mum would have had no idea who attended my sibling's funeral as she was utterly unable to remember the event with any detail.

If someone has gone the extra mile for you regarding support, arrangements (perhaps a family friend who read the eulogy?) I'd possibly send them a card/note. Or even the priest, depending on how well you think he did.

Anyone else, nope. Just as well I don't live in the Netherlands.

I attended a funeral recently and made a substantial donation to the local hospice. I did receive a text to thank me for the donation and the words that I had written in my card, but I absolutely didn't expect anything. The family had more than enough to think about already tbh.

I agree with VeryButchy.
You attend the funeral to give support to the bereaved, not to create work for them.
I would not even have been able to compile a list of who was at any of my sister or parents funerals, let alone track down how to contact them or begin to have the strength to start writing letters or cards.
It is definitely not 'a thing' in England or Wales (been on MN too long to realise that stuff can often be different in other countries, even within the UK )