וְנֶאֶסְפוּ־שָׁ֣מָּה כָל־הָעֲדָרִ֗ים וְגָלֲל֤וּ אֶת־הָאֶ֙בֶן֙ מֵעַל֙ פִּ֣י הַבְּאֵ֔ר וְהִשְׁק֖וּ אֶת־הַצֹּ֑אן וְהֵשִׁ֧יבוּ אֶת־הָאֶ֛בֶן עַל־פִּ֥י הַבְּאֵ֖ר לִמְקֹמָֽהּ׃
And thither were all the flocks gathered; and they rolled the stone from the well’s mouth, and watered the sheep, and put the stone back upon the well’s mouth in its place.—
Rashi on Genesis
ונאספו [AND THITHER WERE ALL THE DROVES] GATHERED — they regularly gathered there because the stone was a heavy one
Radak on Genesis
ונאספו שמה...וגללו, the subject of the verse are the various shepherds who have as yet not been mentioned.