Which expansion cards in base deck?

Hello! Which expansion cards can stay in the base deck Forever? (I possess Collection Edition so I also have mini expansions). When I play, I choose a single expansionvto play (so the Station of New Leaf, or the River from PearlBrook etc). I buyed every expansion but don't know if every card can stay together forever (Pearlbrook seems like I have Always to separate them of I play with another expansion, but New Leaf seems It can stay together). Also, of there are too many cards, It seems super difficult to draw the deck and do do the combos... Thank you!