I have no good knowledge about training grenades that were used after the war, in Russian-controlled Germany.
It is very likely that any type of WW2 Russian trainers were used but I don't know which. F-1 practice, RG-42 practice?
Remaining WW2 stocks of Stielhandgranate 24 and 43 were used, and for this there were several training versions of these stickgrenades.
There is a wide range of manufacturers of this, sometimes civilian made, throwing dummy.

**********************************************************

practice grenades

The grenades explained below this text are 1970's practice devices, as used by the East-German Army (NVA, Nationale Volks Armee). In the same time-period, the Russian UPG-8 was used in practice as well.
They were used to practice throwing with a simulated explosion. They have cast iron bodies and a fuze made of stainless steel.
Grenades were fitted with a special cartridge that had the same caliber as the cartridges for the signal gun (26.5mm/Kal.4).
These cartridges were NOT to be used in such a gun, only as a practice charge for these grenades.
The central canal through the body measures 27,5mm in diameter.

Grenades were manufactured by VEB Lehrgeräte und reparaturwerk, Mittenwalde.

F1 style

Total length : 147mm
Length w/o fuze :
Diameter : 57mm
Weight : 500gram

The right photo shows the replaceable charge that was used with this grenade.

Data and drawing thanks to Peter.
Photos © W. Jordan.

**********************************************************

RGD-5 style

Total length : 120mm
Length w/o fuze :
Diameter : 55mm
Weight : 500gram

Data and drawing thanks to Peter.
Photo © Franz451.

**********************************************************

RG-42 style

Total length :
Length w/o fuze :
Diameter :
Weight :

Photo © Franz451.

**********************************************************