Well since you asked here are a group of unkowns 
that I have no idea where they are from. I think 
most ot them are from non-popular, hentai or echi 
series, but I thought the cel artwork was nice. 
Anyways, here is the first group of them.

Marcus



harmony cel, probably from the end of an episode. 
Found guess it is from a late 80's or early 90's 
mech or military anime.



Probably a hentai or echi series or a fighting 
series.



Character design looks very familiar, but just 
can't place it. The blue back is not the 
background, just used it to show the sweat drops.



No clue where this is from.