Rachel Morris led GB's rowing success with arms-shoulders single sculls gold.
Lauren Rowles and Laurence Whiteley won the trunk-and-arms mixed double sculls and the mixed coxed four added a third gold for ParalympicsGB.
In track cycling, Lora Turnham won the B 3km individual pursuit and the men's C1-5 team claimed sprint gold in a world record time.
Compatriot Neil Fachie won cycling B 1km time trial silver, with Sophie Thornhill, gold medallist in the 1km time trial on Friday, and her pilot Helen Scott taking bronze in the B 3km pursuit.
There were British triathlon silvers for Lauren Steadman in the PT4 and Alison Patrick in the PT5, with Melissa Reid taking bronze in the same event.
GB's Tom Aggar won bronze in the men's arms-shoulders single sculls.
Rowing gold rush for GB
The four rowing medals were won within an hour on the Lagoa water in Rio and Great Britain have now claimed 20 gold medals and 46 overall to sit second in the medal table behind China.
Morris, who had both legs amputated because of complex regional pain syndrome, finished ahead of China's Lili Wang, while Israel's Moran Samuel took bronze.
The Welsh competitor switched to rowing in 2013 and now has three Paralympic medals across two sports, adding to the hand-cycling time trial gold she won in Beijing in 2008 and bronze at London 2012.
"That was the hardest thing I've ever done," she said. "It just goes to show if you have stuff drilled into you every day by the coaches and you do it you can win."
The pairing of Whiteley and Rowles was only created last year, when 18-year-old Rowles switched from wheelchair racing to rowing.
The duo won silver at last year's World Championships and in Rio beat the silver medal-winning pair from China and the third-placed French team to add a Paralympic title to their collection.
James Fox, Pam Relph, Dan Brown and Grace Clough, along with cox Oliver James, defended Great Britain's gold from London 2012 in the mixed coxed four, finishing ahead of the USA and Canada.
GB have dominated this event in recent years, taking gold at the past three World Championships - although only Relph, 26, remains from the boat that prevailed in London four years ago.
"It feels amazing. Coming through that last 250 metres I knew that we had won it," said Relph.
"We knew we were fitter, stronger and faster than our rivals but we still had to deliver."
Cundy doubles up in Rio
Turnham, 26, who has a hereditary sight-loss condition, teamed up with her pilot Corrine Hall to beat New Zealand's Emma Foy to improve on her fourth place at London 2012 and bronze at the World Championships.
Jody Cundy, who won gold in the 1,000m time trial on Friday, Jon-Allan Butterworth and Louis Rolfe, bronze medallist in the C2 3,000m pursuit, beat their own world record, set in qualifying, to take team sprint gold.
The trio clocked a winning time of 48.635 seconds to beat China by 1.279secs.
It was Cundy's seventh Paralympic title across both swimming and Para-cycling and his second in Rio following his disastrous disqualification in the time trial at London 2012.
"After four years ago and being the lowest I've ever been this is probably the highest I've ever been," said the 37-year-old.
"I was properly nervous for the kilo, I didn't really enjoy it that much. But this one, with these two guys, and the way they have been riding in the last couple of months, it's a pleasure to get up there and perform."
London 2012 gold medallist Fachie, who has a congenital eye condition, and his pilot Pete Mitchell finished 0.419 seconds behind gold medallist Tristan Bangma of the Netherlands in the B 1km time trial.
Golds elude GB's Para-triathlon women
Britain had high hopes of bolstering their gold tally in the Para-triathlon, with the event included at a Games for the first time.
But Andy Lewis' PT2 gold on Saturday will be GB's only gold, although the women added two silvers and a bronze.
Steadman, who was born without a lower right arm, had been favourite to add a Paralympic title to her 2013 and 2014 world crowns.
But the 23-year-old former swimmer from Peterborough lost out to the USA's Grace Norman by one minute and four seconds.
In the PT5 classification for visually impaired athletes, world champion Patrick, with her guide Hazel Smith, and world bronze medallist Reid, with her guide Nicole Walters, finished second and third respectively behind Katie Kelly of Australia.
Swimming records tumble
Britain's Bethany Firth and Jessica-Jane Applegate will take their 200m freestyle S14 rivalry into Sunday's final (22:37 BST).
Defending champion Applegate set a new Paralympic record of two minutes 7.95 seconds in her heat, only for Firth, already 100m backstroke gold medallist, to beat that time by 1.99secs.
Tom Hamer set a Paralympic record of 1:57.31 in the 200m freestyle S14 heats and Rebecca Redfearn followed suit in the 100m breaststroke SB13 with a time of 1:17.08.
Their finals are at 22:29 BST and the 22:09 BST respectively on Sunday.
GB's men's wheelchair basketball team made it three wins from three in their group to qualify for the quarter-finals.
They beat Germany 66-52 on Friday and will face London 2012 bronze medallists USA on Monday to decide who will be the Group B winners.
Table tennis medals in the bag
There is the prospect of double gold in table tennis for Britain, after Will Bayley and Rob Davies progressed to their finals.
Bayley, who was born with the muscle-shortening illness arthrogryposis and was a silver medallist four years ago, beat Spain's Jordi Morales 3-1 in the class seven to set up a gold-medal match with Israel Stroh of Brazil on Monday.
Davies, who uses a wheelchair after breaking his neck playing rugby, overcame Endre Major of Hungary 3-1 in his semi-final and will meet south Korean Young Dae Joo in the class 1 final on Tuesday.