Leone Nakarawa scored a hat-trick, while Glenn Bryce got two tries in a 70-10 win over Zebre at Scotstoun
Taqele Naiyaravoro and Duncan Weir, who are also moving on, touched down, while prop Jerry Yanuyanutawa was outstanding throughout.
Gregor told BBC Scotland: "I was really pleased with some individuals, especially those who are leaving the club. They put in huge performances."
Adam Ashe, Greg Peterson and Ali Price were the other try-scorers in a one-sided contest.
"It wasn't perfect," added Gregor. "The first half was a bit loose and we were all a bit disappointed with the way we defended but the second half was much better.
"We played really positive rugby and we found some space."
On Leone Nakarawa, who has been at the Warriors since 2013, Gregor said: "He's shown this year what the club means to him.
"The way he played in the second half against Leinster, when he was captain, and the way he played tonight - outstanding.
"It's been great having him here and we've still got a few games that he's going to be involved in."
Glasgow, who have now won nine matches in a row, travel to Connacht for the final round of league matches next week knowing a draw would be enough to secure a home semi-final, following a shock loss for the Galway side away to Treviso.
"They rested a lot of players, so it will be a different team that we face," Gregor said.
"They have an excellent record at home and it will be a fantastic game to watch. They play open rugby, even more open than we do.
"They are well-coached, well organised, with a good set piece.
"We'll have to play really well to win but we have built up some momentum and we believe we can go there and do it.
"I'm really pleased we are in the play-off for the fifth year in a row. That doesn't happen by luck, it happens with hard work on a daily basis by the players and the staff.
"It's tremendous for Scottish rugby that this team has been able to achieve that."