2 pairs of equal angles
8
A regular hexagon has six equal internal angles of 120 degrees. None of them are right-angles !
A diamond, typically referring to the shape of a rhombus or a geometric figure with four equal sides, has four angles. The sum of the interior angles in any quadrilateral, including a diamond shape, is 360 degrees. In a diamond shape, opposite angles are equal, and adjacent angles are supplementary (adding up to 180 degrees).
4 such as a square
8 if it's an regular octagon
Whether it is a regular or irregular octagon does not matter. An octagon is, by definition, a 2-dimensional figure with eight sides, and therefore with eight angles. A regular octagon will have eight equal angles and an irregular octagon will have eight angles some of which are not equal to the others.
There is only one regular quadrilateral, the square. A regular polygon must have equal sides and equal angles, and in the case of quadrilaterals that is a square.
In a regular nonagon there are 9, if its irregular its dependant.
A heptagon has seven sides. In a regular heptagon all of the sides and angles are equal. In an irregular heptagon the sides and angles are not all equal.
An equilateral triangle, has 3 equal sides and 3 equal angles. However, in a regular equilateral triangles, none of these angles are right angles (90 degrees), they are all 60 degrees.
Hexagons with unequal sides and angles cannot be classified as regular polygons. A regular polygon is defined as having all sides and angles equal, which is not the case for a hexagon with unequal sides and angles. Therefore, while hexagons can take many forms, only those with equal sides and angles meet the criteria for being regular polygons.
As many sides as you like providing that it has 3 or more equal sides and equal interior angles