Of course Skunk #1 has branched off into different phenos/subspecies over the years. Cheese, RKS, Lemon Skunk, LSD, and Green Crack (both American and Canadian versions of it)... Feel free to add any if I'm forgetting them.
Island Sweet Skunk doesn't have any Skunk 1 in it (unless it's in the genetic makeup of Grapefruit), it's [(Sweet Pink Grapefruit x NL Haze) x White Widow]. There's also an Island Cheese strain that has no Skunk 1 in it, just because.
This year I'll be running Lemon Skunk crosses, Cheese crosses, and Stinky Skunks over the next few months. The Lemon Skunk drop has already started with [(Lemon Skunk x SSH) x (Super Lemon Haze x Moonshine Haze)] and [(Lemon Tree x Geist OG) x G13 Hazeplant]. More details to come in my grow thread.
In the fall, if I'm not completely sick of running Skunk genetics by then, I might check out some Green Crack crosses like JOTI's God's Green Crack or HSO's or whatever. I don't really get why Green Crack is its own thing and what differentiates it from the other Skunk phenos enough to justify its own drop.
I'm planning on growing out the ASS x Colombian later this year as part of the stinky Skunk run. Mr. Nice's Shit and G13 x Skunk will be growing right there with it, as will Copa's LSD x Ancient OG and a couple drops from The Nature Farm.