Brown and Zeller scored 19 of the Celtics' season-high 39 first-quarter points and Thomas finished with 21 to lead Boston in a 128-98 rout of the Orlando Magic on Friday night.
Brown and Zeller entered the night averaging nine points between them, but finished with a combined 30.
"That's a huge lift when you can get guys who don't always score at that rate to give you that kind of boost," Celtics coach Brad Stevens said.
Thomas, named an All-Star reserve for the Eastern Conference on Thursday, notched his 30th straight 20-point contest. He is 10 games shy of the franchise mark set by John Havlicek.
But Thomas was certainly aware of his All-Star nomination.
"It's expected," said Thomas, the East's leading scorer averaging 28.9 points per game. "God has blessed me in numerous ways and I'm appreciative, but I expect it out of myself."
Brown finished with a career-high 20 points, besting his previous high of 19 against the Cavaliers in Cleveland on Nov. 3. He believes he should have scored even more.
"I really could have had like 30 points," said Brown, who also grabbed a career-best eight rebounds and was 6 of 13 from the field and 6 of 8 at the free throw line. "I missed like four layups and two free throws."
Zeller finished with 10 in his first game action since Dec. 29. The backup big was sidelined for 12 games with a lingering sinus infection.
"It seems like it's been forever. I've missed (playing)," Zeller said. "You're sitting over there and you're just kind of biting at the bit to be able to get back out there."
The Magic last beat the Celtics in Boston on Feb. 7, 2010, when Dwight Howard was still on the team.
The win tied the Celtics' largest margin of victory this season. Their previous high was a 117-87 rout of the Magic in Orlando in their first meeting on Dec. 7.
Nikola Vucevic had 14 points and seven rebounds and Damjan Rudez had a season-high 14 points off the bench for Orlando (18-30), which has lost three straight and 12 of 15.
"I think we're frustrated," Magic coach Frank Vogel said. "I think we're undermanned and I think we have guys trying to perform roles that are outside their realm. It doesn't look very pretty right now."
The Magic's 30-point loss is tied for their second-biggest defeat of the season.
"We need to learn that we have to play harder if we're going to win," said Orlando's Aaron Gordon, who had 13 points on 4-of-13 shooting.
Boston extended its 68-48 halftime lead to as many as 39 points in the third quarter and 40 in the fourth. Thomas subbed out with 2:11 remaining in the third and didn't return.
Brown notched his career-high point total on a driving layup with 3:52 left in the game.
Boston broke a 15-all tie with a 24-9 run to end the period.
Bismack Biyombo's dunk with 9:02 on the clock in the second brought the Magic within 14, but that was as close as they would come for the remainder of the night.
Thomas' pull-up 3 with 29.4 seconds left in the quarter gave the Celtics a season high in first-half points with 66 and Brown's ensuing layup put the Celtics up by 20 at halftime.
-- Boston C Al Horford (groin) did not play and is probable for Saturday's game at Milwaukee. Horford tweaked his groin Wednesday against Houston. "(He) went through a workout this morning, actually felt pretty good but not quite 100 percent," Celtics coach Brad Stevens said.
-- G Avery Bradley (sore right Achilles) missed his fifth straight game and won't travel for Saturday's game.
-- Orlando G D.J. Augustin returned after missing a game with a right ankle sprain. G Evan Fournier (sore right foot) participated in shootaround Friday but missed his seventh consecutive game. G C.J. Wilcox (left Achilles tendinitis) missed his ninth in a row.
-- Stevens could join Thomas at the All-Star Game if Boston clinches the East's first- or second-best first-half record. "I'd get more minutes," Thomas joked.
-- Celtics F Jaylen Brown said he declined an invitation to participate in the All-Star Game dunk contest. "I thank the NBA for asking me," Brown said. "I decided to pass ... to try to help my team get better."
-- Orlando hasn't had an All-Star since C Dwight Howard in the 2011-12 season.
-- The Magic visit Toronto on Sunday.