Looks like styrofoam insulation pellets! Mystery snail eggs certainly don't look like that. Even if they were laid where a bubbler is on at fire hose strength they'd likely shift as a lump instead of spread out individually.
Who else lives in the tank, and have you researched what their eggs would look like?
Still, seems less like eggs and more like inert matter. Have you reached in and scooped a few up to see if they're hard, mushy, etc?