Category-type naming games. How many types of desserts can you name? How many countries can you name? How many different characters in Harry Potter can you name? Etc.
First letter/last letter. Not sure if there’s really a name for this game, but one person starts by picking a word (usually we like to pick a theme, like Marvel or Harry Potter). The next person had to think of a word that starts with the last letter of that previous word, still within the theme (if you are using one). For example, if the first person says “Harry,” the next person has to think of a word that starts with a “y.” Then we go around the car taking turns until someone gets stuck!