Beings, as in human beings.
Loof is not a word. There is a word aloof, which being an adjective has no plural form.
Being a preposition, beside has no plural form. The word besides, meaning "also," is not a plural form, but rather an adverbial genitive.
The plural form for the demonstrative pronoun this is these.
The plural form of the word inferno is infernos.
The plural form is ranches.
There is no plural word for if.
There is no plural form for the word, countries. This word itself is a plural.
The plural form is data.
The plural form for the word 'pioneer' is pioneers.
The plural form of the word "baby" is "babies."
The plural form of the word "pharynx" is "pharynges."
The plural form of vow is vows.