Any pet needs some looking after, especially at the beginning when you are getting the environment right for a new animal. However, there are some pets that need much less time than others.
A tortoise, if you have a fair-sized garden, can be a very easy pet. It needs a safe enclosed space to wander in - people used to drill holes in their shells and tie them with a string, but it is now confirmed that this is a bad thing to do - but will happily eat grass and small plants, and normally doesn't need much daily care. They do need special care around hibernation time though, and can have unexpected illnesses, so do some research first.
Fish don't need much daily care, but keeping the water clean and the temperature right can be a chore - it depends on the type of fish, size of tank and other points - you can get some useful tips here.
Some people like to get a more unusual pet like an insect or snake, which can often be easier to look after especially when it comes to feeding. But whatever you go for, you need to get detailed advice first - no pet comes without responsibility.