How many bits of entropy is a Bitcoin address? I've seen references to 160 bits of entropy, but I'm not sure if this is universal or just applies to the old address format.
For Pay2PubKey addresses, it's always 160 bits of entropy, regardless of the address format (old, 1... or the new Bech32 format)

Pay2ScriptHash addresses, in the old Base58 format (3...) have 160 bits of entropy.  In Bech32, they have 256 bits. You can read more about why the developers increased it here and here.