Since a couple days ago I hear a slight crackling grinding when starting up the car coming from the engine i think and then there is a grinding/scraping noise when I reverse out slowly or move forward. I can feel some vibrations under my feet. The grinding noise only occurs initially when driving out of my driveway etc. and then always disappears once I start moving faster. This all comes and goes. Sometimes I'll hear nothing and later in the day when I drive again the sound will come back. Already took it to a shop and but couldn't find anything out of the ordinary, but this time I was able to capture it on video at least.

When in D I hear the sound, and in park it goes away as you'll see below. The same noise also came on when I aired out, and stayed that way until I aired back up. Never had any issues before regarding this sound. Nothing new installed recently either.
Video for reference:

 

You can hear the noise in the video near the end for sure.
Since it doesn't happen in Park, then I'm guessing that something is being loaded up when you shift to Drive.
If I had to guess, I would say it's something being driven by the serpentine belt of the engine...like the waterpump.
I would suggest having someone in the car shift it to Drive while you have the hood open and you listen around the belt area for the noise.

 

I would check the oil level, it's probably time for a oil change.

 

.00001% chance
Something being driven by the belt, as already suggested is likely.

 

Will certainly look into that. Any reason why the scraping sound comes on when I air out? Is that suspension related at all?

 

At a guess...when you air out there are parts of the vehicle touching the ground that were never meant to, so that contact with the ground could just be amplifying the noise.
When you air up and the chassis is off the ground, everything returns to it's natural resonance and at the moment the noise stops.
Think of holding a jackhammer in the air while it's on versus when it's touching the ground and it's on...it can't really make much noise in the air, but on the ground it's hella loud.

 

Yeah that makes sense although there wasn't any unusual noise before I aired out which makes it more confusing. Problem is trying to have my friend or any mechanic actually experience the problem/noise to get an idea of where to pinpoint the source. Anytime I try to show it to someone theres no issues of course. And then when I'm on my own it comes back. Classic car problems. Some say it could be transmission related. Really hope its just something minor. I'm only 35k miles...