Hi Tony,
It wasn't long ago I was putting together my loose run and I decided to go for major variants
like Bespin Guard tash, Leia Bespin Turtle and flesh neck, IG88, Luke Jedi blue and green sabre,
Lando bespin teeth and no teeth etc. And colour variations like Leia Hoth Red and brown hair,
Bossk, Walrusman tusks. Luke Framboy hair colour variants etc.
You can then move onto more expensive variants like Tusken Hollow tube, Moulded Leg Han Hoth,
Moulded face Luke Jedi, Unpainted knee Fett.
The list goes on. I never really got into COO variants, but as you pick figures up you can do that aswell.
I had great fun putting together my loose run and I would strongly recommend trying to complete it.
Good luck with what you choose buddy