Q: Is it possible to find your apple pencil through Bluetooth? I've lost mine and I've been walking around the house trying to get it to connect to Bluetooth

no

If it was idle and went into sleep mode, no it will not pair just because the iPad Pro is now within range.  You would have to have the Apple Pencil in hand and tap it to the screen to begin using it to wake it up and cause it to actively re-pair with the iPad Pro.  That is part of the power saving functions of the pencil - it does not actively poll for the presence of the iPad once it has been idle and gone into sleep mode.

Currently their is no way to locate it via Bluetooth.  I know that the "Jot' stylus (a non Apple product) has an app to locate it via Bluetooth like a beacon. you can also buy square Bluetooth chip things to attach to keys, remotes, cats, dogs, etc.  the problem is that with current Bluetooth technology and the size of the tech, this does not work too well and Apple doesn't like to release products unless they work near perfect. How awesome does the Apple Pencil work, awesome.  A few Bluetooth chip locator products also make an audible sound, now THAT would be extra helpful. But that also uses more battery to have to keep sending out a constant wide far Bluetooth signal.

So in other words, Apple engineers must have surely thought about it.