Here is a core that I think works well in UU
Quagsire
impish; 252 hp, 252 def; unaware; leftovers, toxic, encore, recover, earthquake
Porygon 2
calm; 252 hp, 252 sp.d; trace; eviolite; toxic, recover, ice beam, and tbolt
Gligar
impish; 252 hp 252 def; immunity; eviolite; toxic, roost...