If I accidentally deleted certain photos from iCloud, is there a way to recover them?

They will be in the Recently Deleted folder for 30 days. After that, it is removed from all devices and there is no way that can be recovered.

Recover them from Recently Deleted. See: If you're missing photos or videos in the Photos app - Apple Support

Are you sure you didn’t do ANY of these ways of preserving photos and videos?

• emailed, texted or messaged the photos to friends or family
• iCloud photo sync
• Transfer your photos to your computer via USB cable
• Apple Photo Stream
• Sync to Google Photos
• Sync to some other photo archiving service such as Shutterfly
• Sync to Dropbox
• Sync to box.com
• Sync to Microsoft OneDrive
• Sync to Amazon Photos
• back up to Livedrive
• Backup to any other backup or archiving service

A final option is if you synced your photos to iCloud, you have a Mac, and you use Time Machine to back up your Mac automatically, you can open Time Machine and restore the photo library to an earlier date. To do this on your Mac open Finder, then click on Pictures in the sidebar and launch Time Machine. Go to a time before the photos were deleted and restore

Photos Library.photoslibrary. (If you had ever changed the name of the photo library restore that file instead).

If the answer is no to all of the above your photos are gone forever.