I myself am not a fan of altcoins other than popular coins. but if you really want to buy one from the list of coins you mentioned above. I prefer to choose IOTA, this is just a prediction, because the price has dropped a lot, maybe the IOTA price will go up again soon. That's just my speculation, and I will not be buying all three. because I believe more in eth and xrp, these two coins are coins that have been around for a long time. and I believe the price of eth and xrp will be higher in the future.