Custom trigger?

Feature idea: what about custom additional triggers?

So today, we have:
! - date
@ - (I use for people, by convention)

- (I use for topics, by convention)

[[ - internal link

Could we have additional triggers like @ and # for additional ‘types’?

for example, I might want $ to be stock names, or & to be family members or favorite books, or whatever else custom list that might be useful.

I don’t understand. Are you visualizing something all the way down to the details? What would My dad &Bob accomplish that My dad @Bob doesn’t already accomplish?