In addition to browsing through the plugins in the Marketplace tab, you can also use the search bar at the top of the window to find specific plugins. For example, if I'd like to search for more themes for my PyCharm, I type in theme in the search bar and hit Enter, which return the following results:
By the way, to be able to search for the plugins in a more extensive and exhaustive way, we can head to plugins.jetbrains.com/pycharm, which contains more categories and searching capabilities for PyCharm plugins. Specifically, we can browse through the list of plugins on the ...