Depends on the frequencies you are looking to block. Low frequencies(heavy base, drums) you need high mass. Like a rubber ect.

Mid and low frequencies fiberglass, rock wholl, foam. Ect.

For what it’s worth you can check out the governments STC 50 wall detail found on page 19 (pdf p.33) of ICD 705 liked below.

ICD 705

If you are looking to block lots of low frequencies you need to curb your expect unless you are ready to drop serious $$ as it’s extremely hard to stop but sound cow makes some great products but expensive.

sound cow

Really for any residential application just get as close to the STC 50 wall detail as you can within reason. Note the double layers of drywall.