So I'm really new to playing DnD, I was thinking about different class/race character combos. I was wondering if the different druid forms are relative to the race size. Like for example, if I were a Druid Goliath and I transformed into a bear, would the size of the bear be relative to the size of the Goliath. Because I kinda like the idea of being able to transform into absurdly large bear or even better a very large goat. I know a few forms have a "Giant" version, but I just wanted to know. Also it would be useful if I ever try to GM.
No, the wild shape maintan the size of the beast, as it is reported in the beast's statistic. As a Druid Goliath, if you transform into a Rat, your size is Tiny.
Which lends itself to some problem solving options for the druid. A goliath turned rat can now get through the small hole/tunnel to access the aurumvorax's treasure pile. The reverse works too; a gnome druid transforms into a bear and now has enough mass to push the rock off the comrade's leg. Go shapechanging!