2 Arbitrage
Arbitraging is not a scam. But what you described is a scam, which is not arbitrage. What you described above are fake exchanges.
3 Smart contracts scam
You can read more about smart contract scam:
https://cryptoadventure.com/community/articles/an-overview-of-smart-contracts-scams/Airdrops can be included as one, but not all airdrops because some airdrop scammers may not go up to creating anything like smart contract.
5 Social media exchange
People may not understand this until you explain about it. Example is the Elon Musk Saturday Night Life in which there was a break and an ads appeared that people should pay doge to an address and receive double (any Nigerian one did not come my mind right now). Or phishing by impersonation which we know is common among Nigerian scammers. Dating scam is also very common. Phishing messages on Whatsapp etc. There are many of them and Nigerian scammers are common with this. I think this scam is also all over the world, although I noticed it among Nigerians more because we are in Nigeria.
1 Don't invest your coins on ponzi / pyramid schemes, they are quite easy to know and one of the basic way is platform that offer you more money for referal than doing any basic tasks
Best use that people should make research before investing and they should avoid hyip schemes, I means investment of too good to be true promised which is your number 5.
3 you can stake your coins on exchanges that do allow staking, some good decentralise exchanges do support some staking of some coins.
Not you keys not your coins. It is better to stake directly on noncustodial wallets or by providing liquidity on decentralized exchanges. I do not know much about altcoins, I may not be exactly correct about providing liquidity on decentralized exchanges. DYOR. People should know that DeFi and DAO are vulnerable to exploits. There is nothing better than holding on noncustodial wallet. Offline wallets are the safest and most secure.