1. Drug use. Let's have this meaning, drugs like, alcohol, marijuana since these seem to be two big "that's sinful"s; but also putting in all manner of drugs from LSD to cocaine to, whatever the streets are hawking these days. Also, would we add drugs to this list? Not, drug drugs; but, drugs like from a pharmacy?
Not all sins are listed in the 10 commandments. I suppose you could put a lot of stuff under not worshiping idols if you allegoricalize it a bit, or not honoring your parents. For drug use, maybe pharmakeia? Sorcery in Galatians?
2. Fornication. This one gets people hopping mad at this "sin" but I don't see it on the ten commandments, so why is this a sin? Technically this word in scripture looks to mean "prostitution" but people seem to categorize it as relations prior to marriage; so I'm giving it its own place on the list.
It's not in the 10 commandments, but it's still a sin. There was a death penalty for it in the case of a girl who fornicates, gets married off as a virgin with a bride price, and is discovered. There are also different varieties of fornication that are specifically mentioned, incest, homosexual sin, etc. Male homosexual sex had a death penalty like adultery.
3. Gambling. Sinful breaking of a commandment?
I know of no specific commands about it, but there is a command about coveting and Proverbs about the way money works. Gambling is getting money without working. There is teaching against being foolish. Some gambling certainly falls into that category.
It is also poor stewardship to throw your money down the toilet when you need money to buy milk for the kids, but there is no commandment against throwing money down the toilet.
If people are playing some game using pennies, just for fun, not large amounts of money, I can't really say that's a sin. But there is some major poor stewardship that falls into the gambling category.
4. Musical instruments in the church service?
Why would that be considered a sin?
The Bible does not call dancing a sin. David did it. Psalms command it. Jesus said, "I have piped unto you but ye have not danced." It's a metaphor, but why would he say that if dancing were a sin.
There are some types of dancing that may not be appropriate, rubbing ones body seductively against a single person or person married to someone else, nude public pole dancing, etc. But dancing in general is not a sin.
See fornication. It's the same thing. Generally, society might think the 'lower class ones work for less. Some prostitutes (regular fornicators) work for free.
7. What about occult practitioners? Here I mean, people who are professing Christians who practice "magick" (yes, with a "k"; it's ridiculous, I know but that's how they spell it). All of their occult rituals are all "in the name of Christ" and they call it "Christian white magick": I presume this can get people stomping mad at sin, but where is the commandment?
There are commandments in the Torah against this. New Testament? Well, they burnt books. I could say pharmakeia again.
8. Tatoos and piercings? Is this a sinful practice?
It was forbidden in the Torah. There were 613 or so commandments, not just 10.
The only one that looks "ify" to me is "adultery" but that only in application to Jesus further adding that, even lusting is an act of adultery. But, then again, I'm not married so, can I even commit adultery by lusting? Or, would I have to have a wife to be commiting "mental adultery"?
Other men have wives that could be lusted after, too. Some pretty movie stars are married. Job made a covenant with his eyes that he should not look upon a virgin with lust.
'Lust' has to do with violating the command 'thou shalt not covet.' Same word used in the 10 commandments in the Greek Septuagint if I recall correctly.