Just a few Piorun MANPADS. Nothing that has any range, or can hit ground targets.
I think we need to see what the fragments in Poland say. Whether these were strays (which are not uncommon with Russian missiles), or whether they were attempted interceptions, or what. It's entirely possible that Ukraine launched S-300's at Russian missiles and missed, and they could have landed in Poland.
It doesn't make sense for Russia to target Poland, but they've made a lot of bad miscalculations already so it can't be ruled out either...