Chow_13answered grow question 4 years ago They look like Hypoaspis miles to me. Which are good bug's.Here is a copy/paste from this site. https://greenmethods.com/stratiolaelaps/
Stratiolaelaps scimitus (formerly Hypoaspis miles) is a soil-dwelling mite capable of the prevention, control, and management of sciarid flies, shore flies and various thrips and soil pests. Not only are these mites predators of thripsβ prepupal and pupal stages, they are very effective fungus gnat predators as well. S. scimitus are shipped as adults, immatures and eggs in liter-size shaker canisters filled with a loose vermiculite carrier and a percentage of clean peat, and some bran added for good measure. In this form, S. scimitus are very easy to distribute in the crop. S. scimitus can help prevent thrips from becoming intolerable.