Byegone sounds? The wag in me wants to offer up the words "please" and "thank you"!

Anyhow, what about the call of street newspaper sellers? In Belfast, they used to shout "Sixth Tele" (late version of the Belfast Telegraph) up to about 20 years ago, now it seems to have disappeared.
And what about the high-pitched whistle of the TV after the National Anthem had played and the screen disappeared into a little white dot?
And the sound of car engine starters turning over and over and over (and over) on winter mornings.
A personal one I'll miss is the gentle humming / clicking sound of the linen factory near our house when I was a child in the 1960s, it worked a night shift and the noise of the spinning machines when going to sleep became a comfort.
And cherish some of the sounds while you have them! I have a neighbour who is a keen gardener and until recently used a 1960s Qualcast Panther lawnmower to produce a stripey lawn and clippers to cut his privet hedge. Now I'm left with the sound of powertools!