I think you’re looking at Dash and Bitcoin Cash, though the word “altcoin” is more than “iffy.”
Once Bitcoin Core crashes and burns, I’m pretty sure Bitcoin Cash will be recognized as just Bitcoin. There is a huge wave of companies that put a lot of support into Bitcoin, having faith they’d fix the scaling issue, and when they got shunned over the 2x thing, most of them started the move to Bitcoin Cash.
Dash, to their credit, has worked hard to market their coin, and will continue to do so, in a way other coins just can’t. I expect that to pay off.