What are altcoins that are low-risk? Coins that would have 3-5% growth per annum?
The higher an alt is on the CoinMarketCap list, typically the lower the risk is. If you're looking for the lowest risk altcoin out there I would go with ETH or LTC.
All legitimate alts will most likely increase at a rate of 3% or higher a year. Some of the lower market cap coins have the potential to increase 100+% or more. But they are of course more volatile and hence, more risky.