There are creatures here on earth that would fit the bill if they evolved differently: - monkey - dry-land octopus - eagle with four claws (perch on the back

There are creatures here on earth that would fit the bill if they evolved differently: - monkey - dry-land octopus - eagle with four claws (perch on the back two and handle things with the front two) - big raccoon (yikes!) - big spider - honey badger - many lizards have hands If any of these could be large enough and smart enough, they’d make a convincing alien. And these are based on Earth creatures - I’d expect a huge variety of much weirder things in a Star Trek universe.