well, lots of altcoin prices are down at the moment. try to look at potential coins such as xrp, xlm, or others. I think, the coin has the potential to have a high price in the future. but, everyone has their own altcoin options.
Was definitely a good time to buy alts just less than a week ago when Bitcoin shed off 40%. I wish I took the time to add on a bit to my existing holdings, but never mind. As I mentioned earlier I already broke even +1% profit on two coins (Digibyte and Siacoin) so whatever I have left I never need to look back and worry.
Now Bitcoin is back at $15k levels. Either it goes back down as I think it will, then you get yet another alt buy opportunity. Or if does not look back, in which case alts you buy now look attractive but will go even further down in value until the next BTC dip, which may take months.