A common plot device in the 1980's Teenage Mutant Ninja Turtles cartoon is the Dimensional Portal, which operates in a similar manner to a Stargate, except for the fact that it links parallel dimensions rather than different points in a single dimension.
Most of the time (at least 90%) of the time a dimensional portal is used, it is used to transport people between our universe and Dimension X, the home of Krang, the Rock Soldiers, and the Hot Rodding Teenagers, but other dimensions are occasionally shown, such as the home of Usagi Yojimbo, which doesn't look anything like Dimension X. I also seem to recall a Lovecraftian dimension with a Cthulhu-like creature, but I may be misremembering.
How many dimensions are there in the series? Is this similar to Star Trek, in which there are an infinite number of dimensions (e.g. see here), but only a small number of dimensions that have an ongoing importance to the plot, or is the number of dimensions actually sharply limited?
E.g. was the prevalence of Dimension X in the series primarily a reflection of the fact that it was the home dimension of many characters involved in the conflicts shown in the series, or were there essentially very few other places to go through the Dimensional Portal that were interesting or at least unlikely to kill visitors (e.g. I can imagine a character switching a dial through dimensions saying "lava, Cthulhu, more lava, Cthulhu, killer bees, no air or light, earthquakes and -200 degrees, ah, Dimension X, at least we won't immediately die on arrival, let's go")?