wallet - Copy.dat
wallet.dat
wallet.dat.1
wallet.dat.zip
wallet.tar
wallet.tar.gz
wallet.zip
wallet_backup.dat
wallet_backup.dat.1
wallet_backup.dat.zip
wallet_backup.zip
That's a great reminder of what you shouldn't do guys. If you have a wallet, try to keep it on an offline machine most of the time. Just buy a hard drive and unplug it when you're not planning to send any transactions or even better buy yourself a machine to be used only for your cryptocurrency wallets.
Second thing is naming the files. If you are planning to save your wallet backup, rename it! The best way is to change both the name and its extension.