Some phones had a slot where you could insert made to fit cards with common numbers.

Some had custom numbers that could be dialed by pressing the “mem” key followed by a number key. There would be a little slip of paper which you would write in “1: Grandma, 2: Dad work…”. Simpler times.

This is called "speed dial" and it's still a standard feature on desk phones.

You know, in the year 2000, we'll all be on speed dial.

https://amphetamem.es/meme?id=seinfeld_08_20_145&timestamp=0...

That reminds me of how things I considered mandatory previously (carrying small notebook + pen). They weren't mandatory, and most people won't do the manual thing. Don't get me wrong, you'd keep important addresses, say, your grandma out of town. And of course, professionally. But by and large, people just expected you to be in the phone book and vice versa. It also meant calling someone you knew without explicitly being given their number wasn't a faux pas. Now that I think about it, a lot of things were easier. Sigh