Here's a map and detailed explanation of what each does, including on the Pi 4. The jack plug and socket are a very common form of connector. There are at least four versions of the VGA connector, which are the three-row 15 pin DE-15 (also called mini sub D15) in original and DDC2 pinouts, a less featureful and far less common 9-pin VGA, and a Mini-VGA used for laptops.
Finally the optional final letter designates the number of pins, no letter implies 2 pins as does a d for double. There are an additional two 10amp plug variants, one fitted with two round power pins, and
How many pins does socket r have The six-position plug and jack commonly used for telephone line connections may be used for RJ11, RJ14 or even RJ25, all of which are actually names of interface standards that use this physical connector.
