Yes, almost anything can be an interjection,for instance "DOOM!" could even be one.
"Xcuse me" and "Xcellent" are interjections that start with the letter X.
'But' is an interjection that begins with the letter 'b'.
Interpolation
Some interjections that start with the letter J include "jeez," "jolly," and "just."
Quiet!
fiddlesticks
"Wow" is an interjection that starts with the letter L.
Kapish is an interjection. It is slang for "Do you understand?"
"Ah!" "Awwwww!" "A-ha!" etc....
Diamonds, dangling earrings, and doctor's bags are accessories that start with the letter D.
A dishwasher is a machine. It begins with the letter d.
There are no countries in Asia that begin with the letter D.