From United, Park and Valencia are good calls. Park was great in 10/11 and awful in 11/12, Valencia had a good 11/12 but the moment he was given that 7 jersey he was a really poor winger.
I'd add Berbatov.
10/11 (United): 21 goals, PL top scorer
11/12 (United): benched but scored 9 in 13 starts
12/13 (Fulham): 15 goals in 32 starts, almost 1 in 2, quite good at a weak club.
13/14 (Fulham and Monaco) 14 in 30 starts combined, only 5 goals till December at Fulham, recovered strongly in France, 9 in 11.
14/15 (Monaco)- 9 in 29, mostly tap-ins. Form falls dramatically, increasingly benched.
15/16 - totally failed in the Greek league. 1 in 9.
Later he had zero impact in the Indian league too.
He had 1 excellent half-season in the French league, then a fairly poor season and he couldn't hack it in Greece. It was quite dramatic, within about a year he was over.