A couple of people have mentioned glycine, so the following paper is interesting in this regard:

Glycine supplementation extends lifespan of male and female mice https://onlinelibrary.wiley.com/doi/full/10.1111/acel.12953

They say "these data suggest that excess dietary glycine might depress methionine levels and thus mimic some of the benefits of a low methionine diet."

However the effect is very small "Elevated glycine led to a small (4%–6%) but statistically significant lifespan increase". This pales against the 40% type figures discussed in this article, so limiting methionine and protein (particularly from animal sources) would seem like a better option