DASH and IOTA rank top 10, while TRX ranks top 11 by matket capitalization, but it seems that they are not as famous as the other altcoins. Too weird...
I know these coins, but I have never bought them. My way to get cryptocurrencies is to participate in ICO crowdfunding.
Well, everyone sure do have their own ways in which they at least are a part of the market, but the fact that the OP said he has not heard them or saying they are not as popular as other altcoins, simply would make me to believe he is either a newcomer in the market and like someone said, he should speak for himself, or is probably someone who has not been observant at all.
Dash, IOTA and TRX are like the altcoins you would not mention when you are talking about altcoins in general, and most especially, anyone who said he has never heard of DASH, still have a lot of things to get their head around in this market, I am so sure of that.