You're right, keygens are illegal and against the boards posting guidelines:
https://www.techspot.com/vb/topic33297.html
I do think your question does require an answer though
is there a keygen that doesnt have a virus anywhere or from a reliable source?
These keygens, are NEVER provided from a reliable source, actually the source is actually an illegal site to allow them.
So why do the sites exist?
There are a number of reasons:
1. The site is new (and not yet checked)
2. The site is in a country that does not care for these laws (usually not being yours!)
3. The site is used by the game manufactures, to lock down their games even further, and to find out what keys are recorded as illegal
4. The site is used to distribute viruses (also illegal) and hacking files
You are best advised not to use these sites (or search for these programs)
Why again?
1. It's illegal (must be number 1)
2. You may (and likely will) receive Viruses and Trojans (let alone many other files)
3. The game manufactures use income from these games to make better games
4. You may be prosecuted
5. The game itself may also be affected (especially games with opponents online)
6. You may compromise even your Windows files (the keygen usually writes to Windows registry)
I would suggest you either:
Buy the game
Hire it from a legal game hiring distributor
Play the game online (many games are available online to play - ie no install)
That's why.