The title of your question and your first statement make me think of the dark green to black mucilage like blobs on the soil surface that are Nostoc, a cyanobacteria. But I cannot see it in the depth of your photos.
In its moistened state, it is dark green and slippery. In its dry state, it is black and crusty.  Nostoc is an opportunistic organism in that it will take up residence where turf is already thin and struggling. It seems to thrive where there is lots of moisture, the soil is compacted and phosphorous levels are high (things that need correction to minimize Nostoc). The best solution is a healthy lawn to prevent Nostoc from gaining a foothold..
More info on Nostoc and its control in the attached articles:
https://www.canr.msu.edu/news/nostoc_a_green_jelly_like_substance_growing_in_lawns <=links to more articles in this one
https://plantdiseasehandbook.tamu.edu/landscaping/lawn-turf/sorted-by-names-of-diseases/algal-scum/
https://nwdistrict.ifas.ufl.edu/hort/2021/08/11/its-green-gelatinous-and-in-my-lawn/
https://www.purdue.edu/hla/sites/yardandgarden/warm-wet-conditions-prime-for-algae/
https://turfpestlab.psu.edu/pest-profiles/algae/
Two of the photos do show small white objects on grass blades and clover leaves.  But I do not observe damage or death to the plant making me think it might be an insect like a mealy bug or scale insect, but I'm not sure.  I suggest that you take some clearer photos and send them to MSU Plant & Pest Diagnostics (MSU Plant & Pest ID) and go to 'Contact us' to send in images for their review and identification.  Here is an article on how to take good photos: GRASS PHOTOGRAPHY TIPS FOR ID-MSU
If I missed the mark on the 'black grease spots' send in clearer photos of them in another submission for evaluation.
One last item:  I suggest you do a soil test! You will learn about your soil including soil type, pH, nutrient levels and more. Knowing the type and fertility of your soil is the starting point to establishing & maintaining a strong turf or ground cover alternative that can resist diseases, moss, weeds, insects/grubs and look great at an optimal cost. More info here:Don't Guess-Soil Test-MSU or MSU Home Soil Test-self mailer

Hi Dick,

Thank you for all the resources. It definitely doesn't look like nostoc. The shiny black appearance was noticed when I was mowing. After I finished mowing, I went to check it out and take pics. As I got closer to the source, I saw the white. If it is in fact an insect, I'm wondering if the black appearance may have been sooty mold from the honeydew. 

I have had a soil test - for the front yard, not back where this is. Our lot was developed and is backfill. The soil test showed the phosphorous was off the charts. 

Thank you for suggesting the diagnostics submission. I will try to get better images and submit those. Hopefully this is just a turf grass issue and it won't jump to my desired plantings.

Thank you for your assistance,

Jean

Duh!  Sometimes there is a disconnect upstairs!  I think the white spots could be slime mold.  Slime molds are mostly harmless mobile amoeba-like organisms that feed mainly on bacteria. During warm, wet weather periods, slime molds migrate onto turfgrass leaf surfaces, producing massive amounts of spore-like structures of varying colors, often forming white, yellow, orange, blue, or gray patches in turf.  More info in the attached links:
https://ohioline.osu.edu/factsheet/HYG-3074
https://www.canr.msu.edu/ipm/diseases/slime-mold
https://extension.psu.edu/turfgrass-diseases-slime-molds
https://www.extension.purdue.edu/extmedia/BP/BP-112-W.pdf

I think you nailed it on this one. It definitely looks like that slime mold on the OH fact sheet.

When I took more photos this weekend, it looked dead/dried up, which aligns to this as we have been a bit drier recently.

Thanks so much for your help - it is greatly appreciated!