There are cards like
Boggart Ram-Gang and
Boros Reckoner that you still probably want to keep in your respective mono-colour sections, and then your
Kitchen Finks and
Murderous Redcaps that are super versatile and go into almost every deck. If you have an eight-man, I'd wager that only one person at the table wouldn't be able to cast a Redcap, assuming you run halfway decent fixing.
This is why it's not a stretch to consider a lot of hybrids to be artifacts, since they're essentially competing for space with the colourless cards. It also allows you to lower the bar for playability on hybrids, since nearly every deck can run them. As an example,
Curse of Chains might not make the cut in either monowhite or monoblue, but it's decent enough of a removal spell that can go in most every deck. Enough so that I've been running it for over two years at this point, and seen it do solid work.
I think we all agree the scale for ease of casting goes:
Colorless >> Hybrid >> Monocolour >> Gold
If you classify your cards into only three sections (colorless/mono/gold), I'd split the batch of hybrid cards between colorless and mono, based on how you typically see them used. Just.. just don't lump them with gold. Ever.