There are four separate ranges in that technolog stuff.
The Hexagon stuff.
The platformer stuff (which includes the refinery/chemical/biotoxin plant set)
The Syberclicks stuff (uses similar style clips to the Hexagon stuff, only the clips are a lot smaller) at least two sets.
The "Power plant" stuff (at least two sets)
They are all made from the same metallic injection moulded styrene plastic, but each distinct range uses different sized clips or linking bits from the others. The Hexagon, powerstation and syberclicks cannot be interconnected with each other or the platformer or vice-versa.
I have about a dozen pieces of terrain using the first three groups of terrain sets. The others are exceedingly hard to get outside of Russia (and I won't use ebay). The Hexagon, Platformer have been done under licence by Pegasus (and have also been done by Airfix) which accounts for them being more readily available.
From various russian gamers I've chatted with, several of those sets are not permitted to be sold outside of Russian territories (it's a general trade thing, with many companies likewise restricted).