Cool giraffes ♦
As for the question, it's really too wide to give a specific answer.
It depends on your villain, really.
If he plays fit/fold post, you should expand your calling range.
If he barrels a lot, and puts lots of pressure, tighten it.
What does he do against 3bets?
- If he calls them wide, add more hands to the 3b value range. All broadways + most of strong aces should go there. Even a hand like J9s should be a value 3b against some people.
- If he folds or 4bets (and also how much does he 4b), move most of broadways back to the calling range. Add more bluffs (J3s, Q3s, T4s and stuff like that, that would usually be a fold are good hands for that)
But whatever his opening range is (unless it's 10% or so) 3b or calling just 30% is a mistake. It is profitable for your villain to open 100% against you and show a profit even if he openfolds all flops.
Connectors, one-two gappers (especially suited), all Aces and most Kings you don't 3bet, Q6s+, Q8o+, J7s+ should all be easy calls against most villains.
Obviously, don't just start calling all of those hands without feeling comfortable with it. Add them a few hands at a time, and really think about who you're playing against.
Sorry if you knew all of those, once I started writing, it was hard to stop 
