Let me break that down for you:
The bell in Toy Story 3 is your average generic “gong above mechanism” one that you see all the time in fiction. I’m not sure if it’s based off any actual real-life bell & if it is I don’t know which one.
I don’t recall there being any fire alarm devices in The Incredibles 2 (though I’ve only seen it once & don’t remember everything from it), but if there are such feel free to remind me (I do know of either an Edwards 1250/1251-series coded pull or a 270-series station in Toy Story 3 however).
Yes, that is the sound that the Parrs’ smoke detector in The Incredibles makes, but that’s just a stock sound effect used very commonly in media, even though smoke detectors haven’t done 4/6 (as the pattern is actually called) for decades (I’m assuming they started being required to sound in temporal 3 from July 1st, 1996 onward, when NFPA 72 was amended to require that fire alarm notification appliances pulse in temporal 3, & thus it’s logical to infer that this also applied to smoke detectors as well).