With the cassette bots in the G1 cartoon, although they were pets and were sometimes used as a utility, rather than a sentient being, they still seemed to show some form of sentient behaviour, whether it be conversing with their master or other bots. Rumble and Frenzy were very much like this.

Even most of the animal cassettes showed some form of being a sentient being, such as using their own tactics (though questionably, this could be in their programming) and communicating with other cassette bots/cons. (particularly in the case of the Autobot cassettes)

In the Headmasters as well, both the Bots' and Cons' respective cassettes showed remorse for the loss of their master and joy upon their return/resurrection.

This also brings forth the notion that when Blaster and Soundwave were both (brutally) killed in The Headmasters series, their cassette minions stayed living, which contradicts other forms of drones, such as the drone for the Scientist class in FOC, which explodes upon death of the player in multiplayer. (this could be argued against, as it is a game and seperate continuities also affect the laws and physics in that particular universe.)

So, in my own opinion at least, the G1 cassettes pretty much had their own sentimentality and just happened to side themself with their master and take the form of a cassette that takes residence inside of them.

Action Masters are kind of iffy, but I honestly treat them as semi-sentient or as drones.)