The answer will depend on whether the hexagons are all the same size or not, whether they come together in a plane or 3-dimensions, whether they can join at vertices or only sides.
Two hexagons, of the same size, that are coplanar can make a concave hendecagon (meet at side) or a concave dodecagon (meet at vertex).
Two concave hexagons can also join (dovetail) to make one hexagon.
The question is under-specified.
2 hexagons and six triangles
Two hexagons and six rectangles
hexagons
yes
Hexagons.
Hexagons
Infinitely many. You can make a very, very long chain of hexagons, for example.
Crystals form in the shapes of hexagons or six-sided prisms.
A hexagon is a 6 sided polygon
Other hexagons.
Crystals form in the shapes of hexagons or six-sided prisms.
Hexagons, assuming they are polygons.