Q.Unknown Growth On Soil
There was white mold on the tomato grow bag compost when I opened it but I still used it. Now they is an unknown growth on the soil (my tomatoes are growing in)
Certified GKH Gardening Expert
That looks like the parasitic fungus Tremella. There are several species that resemble each other. They are of no harm to you, and are eating another fungus that is present. This is likely due to overly wet soil conditions. I would make sure to allow your soil to dry out down to at least 3 inches between waterings, completely. You can apply a fungicide, but these creatures are, likely, doing a fine job already.
https://www.gardeningknowhow.com/ornamental/fungus-lichen/jelly-fungi-on-trees.htm