The RPG-30 is basically an RPG-27 in tandem with a sub-caliber rocket. These are ballistically matched so that on firing the subcal rocket flies in front of the main rocket, and sets off active protection systems on the target, which hopefully cannot recycle in time to kill the following larger rocket.
RPG-73: Designation for the Polish prototype rocket launchers that became the RPG-76. “73” is apparently from the year of the program start.
RPG-75: The RPG-75 is a well-made, single use, shoulder-fired recoilless launcher made in the Czech Republic. The system uses a high pressure chamber, moving to lower pressure, and can be lighter than standard recoilless launchers.