loose, soft
deep, heavy
neat
vertical

be hidden behind, be hidden by, be hidden in
The troops were hidden by the deep folds of the ground.

fall in folds, hang in folds
The fabric fell in soft folds.
the heavy folds of his cloak

in a/the fold
She hid the note in a fold in her robe.

fold in
a fold in the land

folds of flesh, folds of skin
the loose folds of flesh under her chin

international (BrE)

join
leave
come back into, come back to, return to
be back in
The country is now firmly back in the international fold.

bring sb (back) into, bring sb (back) to
The indigenous people were brought into the Catholic fold.

welcome sb (back) into, welcome sb (back) to
His father finally accepted him back into the family fold.

within a/the fold
opposing viewpoints within the international fold