Is there a name for people who don't believe in a religion yet accepts whatever happens after death?

Atheism. Atheism is anything BUT theism. If you don't adhere to any set of religious beliefs or declare a belief in any god or gods, then you are not a theist. You are then by definition a-theist (not-theist), and are an atheist (welcome to the group). You should do more reading, googling and youtubing on exactly what atheism is and not just listen to the opinions of the others on here as most theists don't seem to grasp exactly what an atheist actually is... good luck.