Counterparts' Children

The counterparts' children are the offspring of the anime's  designed independently by XBrain130, Amethyst-terror, and Taylor Gorrell. Since their parents have the same facial structures, the counterparts' children also have a vague similarity between each other.

Background
In the canon anime, the male counterparts are able to unleash various mysterious powers. (For example entering a a ragefully destructive state when emotionally triggered, the "".) Currently there's no explanantion about what exactly are those powers. However, there are 4 Duel Monsters cards (one for each boy), referred to as the "", which seem to be linked to it. Again, almost nothing is known about them.

Meanwhile, the female counterparts all own a special piece of jewellery, nicknamed "" in analogy to the males' Dragons. The main one in particular, possesses the abilities of teleportation and inter-dimensional travel. tried to gather them all at the, and somehow unite the into one. This implies that either the girls or their bracelets hold some kind of great power. Once more, no information was explained about them.

XBrain130
Many years after that, each male counterpart formed a couple with the female counterpart of the same Dimension, and generated their descendants. Due to the first generation counterparts becoming friends during the events of the, the children were introduced to each other ever since they were babies, and grew as four parts of a large family.

However, some signs show that the second generation may have inherted at least a portion of the parents' powers...

Amethyst-terror
A continuous cycle between parent to child, and it matters not what child may receive. Years after the Interdimensional War created by Leo Akaba, each have settled down and had a child, or two. Depending on which child was suited for the task of carrying a smaller piece of dark and light in them, thanks to their parents.

Much like the counterparts themselves, they are equal halves of a whole. Some end up hating each other, and some end up creating a sibling like bond with them.

But somehow, the new generation of counterparts share a similar.. abilities as a certain parent.

Taylor Gorrell
After the defeat of the new threat to the Dimensions (which occurred three years after Leo Akaba's war on the other Dimensions), all seven pairs of Dimensional counterparts eventually settled down, each having a single child except for Yuya and Zuzu, who had twins. The eight of them have been friends ever since meeting each other as children due to interdimensional transport not being an issue. Upon reaching their late teens and the worldwide reveal of the Dark Synchro Dimension in the 2120s decade, their parents thought it a good idea to send them all to I-SAD for a top-quality education.

There has been no evidence of this version of the Counterparts' children inheriting any of their parents' abilities so far, but they do possess a bond with their fathers' Dimension Dragons. As such, while at I-SAD, all of them have these Dragons in their Decks.

Trivia

 * The last names seen on each of Taylor Gorrell's Counterpart Couples, with the exception of Yuya, Yuzu, and Ruri, are not their real last names: As every counterpart apart from the aforementioned three do not appear to have last names, each of Yuya's counterparts gave themselves one later on, which their corresponding Yuzu counterpart took on when they married each other.