Appropriate game controllers for what you play. Gamepads, arcade sticks, racing wheels and flight sticks all have their uses. Mouse and keyboard isn't always the best control scheme and it's annoying to see steam reviews where people complain about that.
As somebody that doesn't play a lot of racing games or flight sims or anything, a basic gamepad will go a long way. A lot of games that feel bad on keyboard were simply made primarily for console. Dark Souls was an infamous example of this, but this can apply to a surprising amount of things - I find it's hard to reach for numbers in MMOs, and macro keyboards/mice are too busy, but FFXIV actually handles incredibly well on a controller because it was designed with the PS4 in mind. Even with recent games, Armored Core 6, Resident Evil remakes, Elden Ring, Jedi Survivor, I'm sure these all play fine on keyboard and mouse but they're much more comfortable on a gamepad.
A good gamepad is a great catchall if you aren't seriously into any of the genres that utilize specialized controls and are absolutely indispensable for any pc gamer.
Man, I hate gamepads. If a game is clearly meant to be played with a pad and thw kb+m is a garbage afterthought I immediately uninstall. Can't stand them.