NO! Avoid MacKeeper like the plague! The only reason this app is popular is because they are aggressive with advertising, particularly in false pop-ups telling you about how your Mac is infected or your information has been breached. These are scams! Ironically, installing MacKeeper will give you exactly those problems they say they're shielding you from. It's a massive PITA to completely remove from your Mac too.
And macOS in general is good at maintaining itself. Unless you're experiencing hiccups or you think there's something wrong you should be fine without any download any utility apps meant to clean it.
But if you insist, you can look at software like
CleanMyMac (paid) as a general cleaning utility,
Gemini (paid) for getting rid of duplicate files roaming around in your Mac,
AppCleaner (free) or
iTrash (paid) for removing leftover files of apps you uninstall, and then there's also
OnyX (free) and
Cocktail (paid) which are both maintenance utilities. I wouldn't touch either OnyX or Cocktail unless you really know what you're doing lest you can render your computer unworkable. Again, in general, macOS is able to take care of itself and you only lean on these powerful third-party tools when you start experiencing problems. If you are indeed experiencing issues with your Mac, try downloading
EtreCheck which is a free tool that can potentially help you get to the root of whatever problem you may be facing.
My apologies for only recommending paid software in some areas, but I can only recommend apps that I have used and vouch for. For alternatives,
MacUpdate is a decent site where you can search for an app and in many cases it will recommend alternatives submitted by the community.
And finally... if you're looking for anti-virus software, in general you don't need it unless you often visit really shady websites or you're prone to installing random software from unverified sources. In that case, at least get yourself an on-demand anti-malware software and not those that run in the background continually zapping your precious resources. I personally keep
Malwarebytes Anti-Malware for Mac installed which is a
software Malwarebytes originally bought (and rebranded) from a trusted developer who previously made the tool exclusively for exposing malware that may be hiding anywhere in your Mac. Run the anti-malware software whenever you feel an action you took may have inadvertently infected your computer.
Malwarebytes Anti-Malware for Mac has a premium offering, but you can still use it for free as an on-demand anti-malware utility. Paying basically just nets you continuous background checking which is exactly what we're trying to avoid here. The premium feature is great for parents or anybody who are not used to working with computers?the crowd you don't expect to follow on with your suggestion to run a scan whenever they feel at risk?but you probably don't need it.
Hope this helps a bit!