Homosexuality-- if they're both adults/the same age, it's fine. There's nothing wrong with having sex with someone of your own gender.
Pedophilia--the child cannot give consent legally.
Incest--if they're both adults and don't breed, I would be fine. Grossed out by it but fine. Unlike homosexuality, it can be demonstrated that incest is bad as it increases the likelihood of genetic diseases.
Adultery is a shitty thing to do to your partner but we don't need laws against it. The military has laws because members have access to guns and they don't want soldiers to be distracted.
Polygamy/group sex--why do you care if people have sex with multiple people at once?
bestiality--,the animal cannot give consent in any form. see
prostitution--it's been around since the beginning and continue to exists tiday.
suicide/assisted suicide---most people are against suicide. It's going to be awhile before it gains acceptance
pornography--that already exists and with some exceptions, is legal.
duels/gang warfare--duels are out of style. Gang warfare
any kind of drug for any reason---several states have decriminalized mariguana. Don't know about other drugs as I don't do any kind of drugs.