If transforming the folder itself in a module, through the use of a __init__.py file and using from <foldername>  import * suits you, you can iterate over the folder contents
with "os.listdir" or "glob.glob", and import each file ending in ".py" with the __import__ built-in function:
import os
for name in os.listdir("plugins"):
    if name.endswith(".py"):
          #strip the extension
         module = name[:-3]
         # set the module name in the current global name space:
         globals()[module] = __import__(os.path.join("plugins", name)
The benefit of this approach is: it allows you to dynamically pass the module names to __import__ - while the  ìmport statement  needs the module names to be hardcoded, and it allows you to check other things about the files - maybe size, or if they import certain required modules, before importing them.