Sort of on the fence about whether Wout Poels' 2016 LBL win and season in general qualifies. He was a big talent when he came onto the scene with Vacansoleil (and being a member of that team is a giant, bright red flag in its own right), but suffered a horrific injury after crashing in the 2012 Tour and almost lost a kidney. Understandibly he sort of slowed down a bit after that and had pretty mediocre results in both GTs and classics before randomly but not at all unsurprisingly improving significantly almost immediately after joining Sky in 2015. Just as quickly as he became arguably the strongest member of their vast roster of robotic super doms, the entirety of the Clinic (a few ardent Sky apologists aside) collectively called bull on what was going on. 2016 rolls around and he pops up at the final sprint at Liege and beats Albasini and Costa to the line, sending the Clinic further into a frenzy, and then he completely took the p*ss by almost singlehandedly dragging the Sky train through the whole 2016 Tour as the most important domestique by far in a team that included the likes of Henao, Thomas, Nieve and Landa.
He deservedly gets rewarded with a massive three year contract extension with Sky at the end of the 2016 season, securing that retirement nest egg pay day based on an incredible season in true smash and grab fashion, and people start making noises about him being given the chance to win either the Giro or the Vuelta as a team leader. That admittedly didn't actually happen until the 2019 Vuelta and it was a disaster as Poels finished 34th. In terms of other noteworthy wins on his palmares, there's only a couple of GT stage wins and a slew of stages in a bunch of one week tours at World Tour level and a couple of GCs in .Pro and .1 stage races. Nothing anywhere near winning a monument in terms of prestige.
As far as arguments against his inclusion in the thread go, he obviously didn't just drop down into the void of complete uselessness after getting his big contract. His role as a well-compensated super dom will have limited his opportunities to win big races for the entirety of his prime years, although his performances on the road never reached those thermonuclear 2016 heights. He did get a very strong 6th place overall at the 2017 Vuelta while again working as a domestique for overall winner Froome. In 2017 and 2019 he also rode consistenty well in a lot of races and secured more UCI points than in his annus mirabilis of 2016 despite his only wins in those years being stages at Pologne (in 2017) and Dauphine (in 2019). At the end of 2019 his big Sky contract was up and he took that sweet, sweet Middle-Eastern oil money by signing with Bahrain as a team leader. As their main man he managed another 6th place overall at the 2020 Vuelta, although slightly further down on the winner than when he'd been a dom for Sky in 2017 and against a much weaker field overall. He then reverted back to domestique duty with the occasional free role in GTs. He first made an unsuccessful attempt at the KOM jersey at the Tour in 2021 and then switches to stage hunting from breakaways, which gives him two admittedly strong stage wins on hard stages in both the Tour and the Vuelta, both in 2023. Breakaways aside, though, ever since 2016, and in particularly after leaving Sky, he's just sort of... there. Mostly out of sight and out of mind, gradually fading into being pure pack filler. Out of the limelight again, expertly avoiding scrutiny. Nothing like he charging locomotive that sat at the front of the peloton for hours on end, setting a pace murderous enough to essentially neutralise the race. Far from the guy who was at the business end of a monument, outsprinting a former world champion for the win.