So, how about b2x? Which wallet is the best to claim free b2x? I'm not so sure right now.
That's completely irrelevant... B2x got "cancelled", so there is nothing to claim...

Looks like I missed the news, last time a group called Bitpico claim 2x hard fork still alive.
Yesterday, some people said hard fork happening, coinbase halt bitcoin trading due to b2x hard fork, and I've read some articles regarding 2x hard fork. But, just realized there's no any sign of b2x developers.
https://bitcoinmagazine.com/articles/now-segwit2x-hard-fork-has-really-failed-activate/NO2X?
Despite the seeming failure of SegWit2x to take off in any way, it should be noted that there is technically no way to declare a fork like SegWit2x officially dead or failed.
While unlikely, its always possible that the SegWit2x hard fork could proceed at some point in the future. In fact, there is no way to tell whether the SegWit2x chain is currently being mined with a little bit of hash power right now, and it is strictly impossible to foresee whether it will be mined later on. Perhaps a SegWit2x block will be found a day from now, a week from now or even ten years from now, at which point SegWit2x and B2X will technically come into existence.