For me its the ‘Knock Code’ that LG had on their phones (I really wish LG still made at least the V series phones)
Basically there was a four-square area and you set up a sequence of where you would tap to unlock the phone. That set of squares was only shown when you set up the code
Then, to unlock your phone, you would tap those areas in the sequence you set up (even with the screen off).
Fingerprint readers are nice, but I really do miss the knock code
Edit: did find this article with a way to do the knock code, but if done wrong, could brick your phone I guess.
Plus, article is from 2014. When I looked at XDA’s info on it (they also being the developers) it looks like development on it is over, but individual modules may or may not still be supported by their devs
Hardware keyboards on mobile phones
Yes! God I miss my old Droid2.
The Samsung Alias was my.fucking JAM back in the day. Had a two-way hinge that opened in portrait for a standard phone, or landscape for a full keyboard.
The T-Mobile G1 was my favourite phone ever.
There are still some smartphones that have hardware keyboards. Unihertz makes a few (I have the very unwieldy OG Titan). There’s also the Fxtec Pro1 X.
I’d rather have that return than have a foldable.
Bluetooth keyboards