Like the copy/cut commands, the paste command also allows the same three flags:
-e can be specified to also paste entities, if your clipboard contains any
-b can be specified to also paste biomes, if your clipboard contains any
-m <mask> can be used to specify a mask of blocks to paste. Blocks that do not match the mask will not be pasted.
In addition, there are some additional flags:
-a will not paste air from your clipboard. This is the same as -m #existing. The -a and -m flag can be combined (or you can just add #existing to your mask).
-s will set your selection to the area you are pasting into.
-n will set your selection like -s does, but will not actually paste anything. This can be useful to check where your clipboard will end up before actually pasting.
-o will paste the clipboard back to its original origin, as explained above. This will disregard the entire “relative positions”.