A few off the top of my head, from growing up in the 80s in Ireland and in no particular order are:
We used to play in the river in our estate, unsupervised by any adults.
No seatbelts and sitting on someone's lap in the passenger seat or back seat. 8 or 9 people used to squash into a 5 seat car, quite often.
Being left in the sitting room without a fireguard on the coal fire for short periods, from very young.
Crossing main roads without any crossings or adults from aged 6! (That was probably the most dangerous!)
Making tea/coffee for lots of visitors at once from aged 7/8, unsupervised.
Unlimited fizzy drinks on high days and holidays.
Approaching and playing with unknown dogs, as most people used to let dogs out to wander. Very few people in my area actually took their dogs for regular walks in the local area.
Going into other people's houses on the estate, without parental knowledge or permission. Most of these were other children's homes, but some were just single adults or couples who didn't seem to mind random children coming in for a visit!