Hiya, Kevin and welcome!
Agreed that narrow space is too narrow for a snake. Dots and stars always fit in with traditional work, too. Alternatively, there are endless fun, tiny tattoo ideas for at least some areas. Bugs, webbing or just crazy shit. Check of Jeff Rassier. He does lots of weird fillers. https://www.instagram.com/jeffrassier/
That ditch space is large enough for a small piece of it's own for sure. Maybe a flying eyeball?