By safe I mean is not likely to make anything go wrong in your game. If you can find one can you tell me how to catch it?
i'm not sure if you meant glitch like hatching a Pokemon through a glitch or that the mon itself is a glitch, but I assume you meant the last one.
heres the list for gen IV (platinum):
well, I can't guarantee any of them being safe, but don't try the bad egg. ------ is the only one you can perform without a cheating device
gen V (white 2)
you can only see these with a cheating device
i know nothing about glitch pokés, so please don't ask touch about these. you can search for these glitches as bulbapedia is lacking a bit info about them.
here is a list of some other glitches:
again, iknow nothing about glitches, so please just google it rather than asking me as I know absolute nothing.
hope I helped :D