This is the 238th most frequent Polish word.
różnych
"Różnych" means "different" or "various" in English.
The word 'różnych' is used here as an adjective in the genitive plural form, describing the noun 'kategorii' which is also in the genitive plural.
W sklepie były dostępne produkty z różnych kategorii.
In the shop, there were products available from different categories.
Here, 'różnych' operates as an adjective in the genitive plural, qualifying 'restauracji', indicating variety in restaurants.
Ludzie mają różne gusta, dlatego istnieje tyle różnych restauracji.
People have different tastes, that's why there are so many different restaurants.
In this context, 'różnych' modifies 'krajów', being in its genitive plural form to match the governed noun.