There’s a similar situation at my wife’s work. She’s one of nine to be pregnant, all on the same unit. At my work, there’s three of us who are either pregnant or whose wife is pregnant. All pregnancies, both at her work and mine, are due at around the same time.
In HeartGold/SoulSilver specifically (and then not again after for some reason), you could toggle the running shoes. So much nicer than having to hold B all the time. They also allowed for two Select items (items you can activate without entering the items menu), which also never carried over to other games.
I seem to remember one of the more modern games allowing you to view move details (description, power, accuracy, etc) from the movelist screen during a fight, rather than having to go to Pokemon > [Pokemon] > view moves, or whatever it is. I think one game also allowed you to see if the move you’re about to use is super effective or not, but I’m not really a fan of that one. Learning type effectiveness is part of the game imo, but my opinion on this isn’t too strong.
Not really QOL but I loved mega evolution and would like to see it come back. It was exclusive to Gen 6, which was the last Gen I played, but I heard they never included it in following Gens. It was basically a temporary “evolution” (a different form) for specific fully evolved Pokemon for just the fight. Only one Pokemon can mega evolve per fight though, so you gotta choose wisely. Gen 6 competitive battling was peak imo for just that reason.
I really liked the EV training in Gen 6, not sure if that carried over but it made it much easier to increase EVs, rather than having to fight the same Pokemon over and over again.
HMs eventually disappeared. Gen 4 had a whole bunch, then in Gen 5 I think there were still a lot but most weren’t required for progression (I think in order to beat the game you only needed one of the HMs, I can’t remember which. The rest were just for optional stuff I think. It’s been a while though). I think in Gen 7 they finally removed HMs. The moves are still available I think, but they don’t do anything outside of battle.
I’m sure there’s more I’m forgetting, someone else can expand on this list.
She never gives up her dead when the gales of November come early.