For simracing - a set of pedals with a load cell brake. Building muscle memory for the force you push on the brake is so much better than trying to be consistent with the angle of your ankle. The consistency you can achieve with braking is unreal.
Home espresso - a set of accurate scales and a timer. Reducing variables when trying to dial in a new bag of beans or when chasing that perfect cup is so handy. Like the the load cell brakes for sim racing, it allows you to be consistent and just change small things at a time and then stick to what works.