Utility tokens are tied to a certain blockchain or a certain project and the goal is to provide a certain type of utility.
For example, a utility token may offer discounts in term of fees, rewards or other benefits.
Filecoin is a good example.
Filecoin (FIL), is the utility token tied to the decentralised storage network Filecoin. FIL can be used to gain access to the platform's network and/or storage space.
CEX tokens often qualify as utility tokens, too.
For example, Cronos (CRO, for the crypto.com exchange) or Young (YNG, for the Young Exchange platform).