[DonRotolo]

Potentiometers we use a lot, often the mid-price ones ($4 each or so) from Mouser.
Same with limit switches, we pick ones with long levers on them we can bend to fit whatever our application, usually from DigiKey or Mouser.
The maxbotix ultrasonic range sensors are good, but we has poorer results from the very narrow beam type. We only use #1 now.
The gyro and accelerometers from the KoP are pretty good for many applications. Certainly the price is right. The gear tooth sensor, we have not had good success, but I personally do not blame the sensors, they work fine.
Haven't had a need to sense pressure, temperature, and many other physical parameters, but with exceptions most any sensor was legal last year.

I would approach this differently: What do i need to sense, and why, then find something in a catalog to specify how.