Divock Origi
Origi was simultaneously useless around 95% of the time and absolutely vital to Liverpool's championship pursuits during the Klopp era, making his value borderline impossible to pin down.
One would imagine that he never would have been as valuable to another club as he was to Liverpool, making it tough for the club to field a worthwhile offer, and that's likely the case, as he was never sold. But let's take a look at his transfer and valuation history.
Like many players on this list, Origi entered at a very reasonable price. That being said, the only time at which his transfer value even touched €20 million was the end of 2019, a time at which it would have been quite impossible to move on from him at such a price, in the wake of his UCL heroism against Barcelona and Tottenham.
In a vacuum, yes, Liverpool possibly could have squeezed a few quid out of a move for Origi, and he wasn't particularly productive towards the end of his time for the club, but let's be realistic; the name shouted after "corner taken quickly" was absolutely never getting moved until the end of his deal.
Dejan Lovren
The lovable centre-back came over from Southampton, as have so many other Liverpool contributors, for a fee of €25 million, and his market value never got that high as a Red.
He left after the Premier League title in 2020, so there wasn't really a logical exit point before then; he was seen as a key piece in the early Klopp years, saw his value to the club surge after a strong World Cup with Croatia in the wake of the UCL final run in 2018, and was a key depth piece as the club chased trophies in the following seasons.
Alex Oxlade-Chamberlain
Financially, this was one of the worst losses on this list, as Liverpool spent €38 million on the midfielder and never got as much out of him as they did players like Firmino.
His transfer value peaked more or less in that zone, as he never quite lived up to the hype he received from some corners of the English media.
Of course, this was due in part to injuries, which would have made it tough to move him at several different points in time.
Sending a significant fee for a currently-injured player is a hard sell for a lot of teams, so while Liverpool weren't quite getting their money's worth, it's not clear that anyone would have given them a decent deal.