While doing a survey of some NFT collection, the rarity is one of the collection data. But this rarity is relatively difficult to quantify. There are some tools to display the rank and percentage of it.

From the website itself, only properties are displayed which are what rarity based on:

To figure out the relationship between rarity and properties, firstly I looked up the metadata of one NFT which is storing on their server.

The attributes fit the properties of NFT. The percentage of each property indicates the proportion of it in the whole NFT collection.

However, the scores and rank of rarity are defined by each rarity tool provider. Each algorithm is different, and the rarity is not optimistically relevant to the price of NFT. Generally, the rarity model depends on the difference among NFTs. An example is NFTGo Rarity Model.