Here is a short review of the accessories you might add to a crib, most of which are unnecessary:
Bumpers: By the time Lucy moves around enough to bump her head on the crib, she’ll also be old enough to know that bumping her head hurts. After a few bumps, she won’t do it anymore. Because early knowledge is valuable, if slightly painful, I don’t recommend bumpers.
Proppers: These items have not been proven to add any protection against SIDS. The safest way for Lucy to sleep is on her back, which requires no propping. The only exception is babies who suffer flattening of the head from lying on one side too often; in that case, proppers can help keep them off the flat spot in the first couple of months, before they become too wiggly [See: Head Shape].
Blankets: They end up covering the head instead of the body, which isn’t ideal. A sleeping bag that zips around the body is much more convenient at a young age.
Pillows: They can be potential hazards for the same reason as blankets.
Stuffed Animals: They’re fine, as long as they’re not too fluffy.
Mobiles and Hanging Toys: These are fun for Lucy and provide visual stimulation while she’s lying on her back. But don’t overdo it. The world is new to her, and she is curious enough that she won’t need much help to stay interested in it.