Howdy,

After several years in the hobby, I occasionally have heard discussion of
certain groups of plants that do no prosper when in the presence of other
species.

the ones I have heard of:
cryptorynes vs Vallisneria sp.,
Val vs Saggitaria sp.

Do any of you have a more thorough list from your own experience or sources
online?

In nature, it is typical for only one species to dominate a certain niche in
a pond/lake/river. Chemical means are routinely used to get a leg up on the
competition in the rainforest in delightful irony against the stereotype of
"Mother" Nature as being a pristine, nurturing, static thing.

regards,
KL