Ok, so if you already have two 8GB sticks and those are what you are planning to use, then why bother asking:
what ram should I pair it up with
And being as this board utilizes a Quad-channel memory architecture, it doesn't really make a lot of sense to run only 16GB, for the kind of tasks you have in mind, AND only dual channel. You are leaving a lot of performance on the table. I'd say minimum you want a 4x 8GB configuration of matched sticks. Do you even know if the memory you have is actually compatible with this board? And by compatible I don't mean "DDR4 of a certain speed". I mean "compatible", as in, it has been validated at both JEDEC and XMP speeds WITH the exact board you are intending to use.
What is the actual model of the memory kit you have and was it a single kit with two DIMMs that came both in the same blister pack, or is it two separate DIMMs that were purchased individually, regardless of whether they are the same model or not? Do you know if the kit is on the QVL list for this motherboard, or is listed on the memory manufacturer's compatibility list as validated for this board? That is to say, it might still work even if it isn't, but it might also not. Or it might "work" but have "issues".
Knowing the exact kit model would be helpful.