The current all shock gate is the child of constant jelly king farming.
Jelly king is a slime themed gate (duh) and mostly gives purple and blue, the minerals that make shock strata.

So why not add fire, poison and shock themed jellies (ice jellies already exist, they could have similar effects like the ice jelly, would also need a ice lichen) and add a random chance that the Jelly king strata is a Fire, Ice, Poison, Shock or normal Slime gate spawns.