If they’re like little greenish yellowish balls about 1-2mm across then they’d be earthworm eggs
they might actually be good for the plants. If you are growing tomatoes…its tomatoe food to make it grow! It might be healthy for the plants…but it’s a possibility that it might be earthworm eggs so type in earthworn eggs on google images and compare it withthe tomatoe plant food (do it!)
if they are these
they are earthworm eggs. Leave em alone, they are good for your soil
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if they are in your planters, I am sure its fertilizer.
Could be slow release fertilizer like Osmocote: Usually found in potting soil you buy.