DaisyI said:Are the leaves a little succulent? They could be Purslane seedlings. I imagine they came with the plants.
tofitropic said:Another possibility is some type of mini-spurge, Euphorbia prostata, Euphorbia microphylla and other similar. They will exude bit of latex if we cut the stem. it will be easier to know what they are when they are a bit larger. but both purslane and spurge are common weed on succulent grown in container..