What's that noise under the hood? [1999] Lexus eS300 v6 Engine.

Lately I have noticed a small rattling sound as I drive my car. This past week, I felt the rattling get a lot louder. Please see recordings to hear the noise:

https://youtu.be/E7o1uhSYOJY (video) https://vocaroo.com/i/s1KvIVA10RPL (audio)

The noise seems to be around the timing belt box, but I cannot identify exactly where it is coming from. I topped off all the oils this morning and it still seems to be making the noise. One thing I noticed is that the noise disappears after about 15-20 minutes of running the car.

I drive a 1999 Lexus ES300 V6 engine. Does anybody have any idea what may be causing this sound? I had the timing belt replaced about a year ago. Any advise would be greatly appreciated (my mechanic is out of town for another week so I figured I'd ask on here).

Thanks for any input you may have and please ask any questions that may help narrow down the problem.