What lies outside the unobservable Universe? Mike?

There is nothing seen (nor known) outside the observable Universe.

There is nothing outside Universe (observable or not), as we defined 'Universe' to include everything. It isn't that there is a thing called the "Universe".

It is we the humans, who give "names" to "things".

If you ask "What is OUTSIDE the Universe?" Someone answers "X".

Then you ask again "What is OUTSIDE the Universe?" The same someone answers "Y". How many OUTSIDEs can there be. Infinity?

Visit some past notions of ours. Earth was not a planet. 5 centuries ago it became clear on that Earth is indeed a planet.

"World" meant "Universe". Stars were like dots on a wall paper we call "sky" at a fixed distance, till the use of telescope. Distances then began coming to our notice that can be measured in a new unit "Light Year". Now we deal with million or billion Light Year.

About eight decades ago, some cloudy "nebulae" were studied in more detail. Biggest of them in the constellation, Andromeda was found to be a body full of stars, innumerable in number. It was given the name "galaxy". Some more were found (M22 in Triangulam). These were given a name "Island Universes". Harlow Shapley, Cecilia Payne-Gaposhkin & Edwin Hubble blazed new trails. The Universe view we have now was because of their work.

To finish a comment on this my question. The info your getting is its latest because all this happened between 2008 to 11/28/2012 to 12/31/2015. Long before your brain was functionally operating right. Mike

Likely more 'Dark matter', and Solar Systems. Maybe alternate dimensions.

Distances to astronomical objects:

The "unobservable Universe" generally refers to the part of the Big Bang that is beyond our event horizon. That is to say, more than 13.5 billion lightyears.

You seem to be referring to distant parts of our Solar system, which are perhaps 20 light hours away --- about a quadrillion times closer.

There are indeed likely to be more objects like Pluto in the distant reaches of the Solar System.

Upcoming large near-infrared surveys (LSST in particular) will find most or all of these.

The Hubble is not good at finding stuff --- it's good for looking in detail at objects that are already known.

i think its unknown.