Beat me to it! He was my first thought because I don't like spending money on old players. You need to offer him a pretty hefty contract though as he always seems to go to Valencia on 47k/week.
Outside of players that start "old" or "older" in the game- looking at some future saves it seems the best chance to still have some one half decent at a top club is for them to be high in Natural Fitness, Ambition, Professionalism and it seems Determination. Probably Frank Lampard has them all, and at their extreme levels.
I looked at a 12.2 future saves that were posted on the forum. It had about 12-13k players in it and about 600 were 35+ at the start of the game. I then looked at it in 2016, only 200 players were 35+ and severly worse quality than the ones starting the game. The game is so ageist lol
Here's CR7 from the same theme of future saves from 2021 at 36;
Rooney and Modric still look ok at 35, and Reina and Valdes are decent looking going into their late 30s. Let me know if anyone is interested and I'll post some screenies of them aswell