arbitrage is very risky since you can lose a lot of money in it, otherwise it is pretty easy to perform.
why are you looking for bots and algorithms, why not just trade normally?
All types of trading is very risky if you didn't know what you are doing. In arbitrage trading, I believe its very basic and not too much risky if you are good on finding a coin to perform this method. This method will be very risky if the user choose a coin with a huge spread on Buy & SELL price. I use this method before and I can have an easy quick buck by trading to BTC>Preferred Coin>Fiat or ETH> then convert back to BTC.
Leverage trading is the most risky method compared to arbitrage trading. Assessing the risk of this method maybe varies on the style of trader.