If the files were actually removed from your computer, there isn't going to be a super easy way to get them back.
You can check the
"Historical" section of your profile for your most played maps and download those manually. Or if you are a
supporter you can also search for any ranked map you have played in the past on the beatmap search page.
Any unranked or unsubmitted maps are going to be much more difficult to find, and unfortunately you are just going to need to try and remember their names.