There are other parts of speech besides the eight listed above. Here are a couple:
In Chinese, de (written properly as 的), in some cases indicates a possessive. Western scholars call this a particle -- another part of speech.
Another distinct part of speech is the measure word. There are measure words in English: "pair" in the expression "pair of pants". It could be argued that "pair" is a noun, but in this use, it is not.
"Gaggle" in "gaggle of geese" is another example. Again, some will maintain it is a noun, and I don't want to start a war. But the entire phrase is a compound noun and "gaggle" itself -- in this use -- is a measure word.