General suggestionsHow do you know which package is suitable for the assignment? Here are some guidelines:
Libraries consisting of less than three modules are typically too small for you to propertly demonstrate your abilities of reading and understanding code you have not written yourselves. On the other hand, if the library has too many modules, you may want to pick a subset of the library and focus on that. Describe as clearly as possible which part of the library you cover.
The package list on hackage can be a bit daunting, but they are organised in categories and you can search the page for keywords that interest you. It could be wise to choose packages of a domain you are already familiar with. For instance, it could be related to your Bachelor or Master's thesis, or related to some course you are taking (to get some possible synergy effect). And of course, libraries you used in the labs, or discussed in this course's lectures, may be worth considering.
To determine if the package contains the advanced features of Haskell taught in this course, you can check if they use relevant language extensions (such as GADTs or TypeFamilies). These are either declared in the header of the modules or in the .cabal file.
When in doubt, pick a package which is downloaded frequently or is used by many other packages (has many reverse dependencies).