They have been recovered as part of an operation aimed at 'dismantling' organised crime gangs, with much of the focus on Mexborough, where the Pitsmoor Shotta Boys gang operates.
In 2016, nine members were jailed for over 30 years for a range of offences including violent disorder, drug possession, witness intimidation and robbery, with police chiefs claiming at the time that the gang 'brought absolute misery' to Mexborough and members felt they were 'above the law'.
In a further crackdown on organised crime since the beginning of January, 12 arrests have been made.
CRIME: Teen jailed for dragging man into Doncaster underpass and robbing himOfficers have seized a range of drugs, including a one kilo stash of heroin in one raid and 135 wraps of heroin and cocaine in another.
Crack, Spice, two kilos of dried cannabis and 23 cannabis plants were also found in searches of properties across the town.
Two CS gas canisters have also been seized as part of the operation.
Detective Chief Inspector Paul Wilson, of South Yorkshire Police, said: "Since my arrival, I have placed a significant emphasis on disrupting and policing organised crime across the town, by increasing the capability of my organised crime teams and committing a considerable amount of time in addressing this type of criminality, particularly in the Mexborough area.
"In the last 10 weeks alone, we have 12 individuals from Mexborough either sentenced and in prison, or pending court, for serious crimes that will likely carry custodial sentences if convicted. There are others who I also plan to arrest."
He said officers are working with a range of partners including Doncaster Council, Trading Standards, the NHS, schools, social services and licensing officials.
"Part of this approach is the education of our young people, and highlighting the risk and danger of a criminal lifestyle choice that can, at first glance, seem very attractive," said DCI Wilson.
"On the face of it, an individual involved in crime, even at a low level, may appear to some as having a bit of wealth, but in reality they are in fact vulnerable to both lengthy imprisonment, confiscation of all benefits and violent physical attacks by other criminals. We need to educate our young people, of which some can be influenced by this façade, that it shouldn’t be aspired to and this type of individual is a dysfunctional role model.
"This is a sustainable policing plan and it will continue and be focused upon all those involved in organised crime in Doncaster. This is to ensure we reduce offending, increase the seizures of illegal items, recover the proceeds of crime - including houses and vehicles, and equally as important, to increase the quality of life for those members of our communities who are blighted by the behaviour of a few who believe they are above the law.
"We are in fact continually increasing our capability in this area, and we will make even more difference in the weeks and months to come."
As part of the operation high visibility policing patrols have been carried out, land searches were organised to look for hidden weapons, community meetings have been held and an off-road bike operation was mounted.