For me, holding altcoins is something that doesn't require much thought or action, for me the best ones are in the top 5 of CMC, for me they are the most reliable to trade, other altcoins imply much more danger for me because obviously they can fall to nothing, and that is something very unpleasant, if not, ask those who were in Hodl mode on Luna, in this order of days I would say that ETH is much better and I would surely go for MONERO, but seeing that Monero has been delisted from many exchanges it is more difficult, but it is a very good currency for the privacy it provides.