Which word is always used in its plural form (सदैव बहुवचन)?

Certain words in Hindi grammar are strictly used in plural forms due to respect or convention. 'दर्शन' belongs to this category (e.g., "आपके दर्शन हो गए"). Other examples include प्राण, आँसू, हस्ताक्षर, बाल, होश. Words like गाय, लता, and बहन change into respective plurals (गायें, लताएँ, बहनें).