CNA - certified nursing assistant (a certification you can get with a ~2 month class to be a nurses aide. Can work in nursing homes or the hospital.)
LPN - Licensed Practical Nurse (A nurse who takes the NCLEX-PN. Their schooling is about a year and a half. They can do many of the things RNs do, but are not supposed to assess, initiate teaching, hang blood products, give IV push meds, etc. In some states they can take an extra course to be able to do some IV stuff. They are not often hired in hospitals, mostly in nursing homes, rehabs, home health, etc. They get paid considerably less than RNs.)
PCA/PCT - Patient care assistant/personal care aide/Patient care tech, etc (Similar to a CNA, but a certification is not needed. These are usually the nurses aides in hospitals)
CRNP/NP - Certified Registered Nurse Practitioner. (A midlevel provider similar to a physicians assistant. They can prescribe medication among other things. They work in hospitals, doctors offices, nursing homes, etc. Wherever you would expect a PA to work, with the exception of the OR in most cases. They have at least a masters degree and must take a board exam to be licensed in their state.)
CRNA - Certified Registered Nurse Anesthetist (Also a masters degree prepared nurse who administers anesthesia and manages airway during surgical procedures.)
RN - Registered Nurse (Can have a diploma, ADN, or BSN. Takes the NCLEX-RN to become licensed.)
MA - medical assistant (not actually a nurse, but gets thrown around here a lot. Its about a year long program and they mostly work in doctors offices. They can admin some medications and give injections. Some can draw blood work as well.)
Those are the main ones I can think of off the top of my head.