It looks like it could be pieces from the guides in my amateur opinion. Below are some pics I stole from the web. Color seems pretty close. If you search the forum there are a few other posts with a similar color material in the oil pan and the consensus seemed to be timing chain guides. I'd search for a few of those threads, they may be able to give you more info. Or someone more knowledgeable may chime in here.
Any rattling on start up?
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