Within a Pandas dataframe, how to filter so that the columns only display unique values and exclude numeric ranges from this?

I have a large Pandas dataframe. I want to find out what the unique values are within each column. I have figured out how to do this but it also recalls all the numeric values. I want to be able to exclude a range like 1-1000 from my filter so as I can just view strings etc.

Currently I've been using pd.unique()