Its very unlikely to be the last one.
Presidents rather commonly issue pardons that raise eyebrows on the way out of office. Clinton did, Obama did, Trump did. Obama holds the record for volume on the last day, granting a stunning 330 clemencies and pardons combined on January 19th as he was about to leave office. Many of them were commuted sentences handed out for drugs in the height of the drug war.
The only limitation on Presidential pardons in the Constitution is that they cannot block or reverse an impeachment. With that single exception the power is absolute.
But the breadth of this pardon, stretching back to 2014 and forward to the present day, is unprecedented. It covers not just the gun and tax charges which Hunter pled guilty to in September but also any and all conduct that was not subject to current indictment or prosecution dating all the way back to 2014, which incidentally is when we were interfering in Ukraine politics and the Burisma and biolab events linked to him began (at least as far as we know.)
Considering that with few exceptions the Statute of Limitations on federal crimes has run out after six years on virtually anything back to 2014 this raises a serious question: Exactly what is envisioned that might have actually been open and subject to potential prosecution?
Joe Biden and the Democrat Party have often tried to maintain that nobody is above the law. Apparently that does not apply to Joe Biden's family, and the implication of the pardon in the way it was drawn is that there is much more, including likely conduct not subject to the Statute of Limitations, that he is now immune from the consequences of.
Many have said this "further damages" the faith Americans have in the US Justice system.
Frankly, for me anyway that faith was flushed a long time ago, but if you still had some sort of silly belief that we actually have a justice system that serves all without fear or favor you need only read 8 USC 1324 and contemplate the people who ought to be doing 10 years or even life in prison under that Statute, which dates to the 1950s, to be disabused of that.
Thus from my point of view I am neither surprised nor do I expect any of this to change -- and if the same standards are applied by the other side, well, that's called "what's fair for one is fair for the other." If that's how Americans choose to see things and allow it to continue then so be it. I will govern myself accordingly and you should consider doing so as well.