Thanks !

Rhae was the "love potion" one - altho it's probably just kids talk because it's the one and only occurence of a love potion ever been mentioned in Westeros (I know a lot of people base their theories on this anecdote, like Jeyne giving love potions to Robb, but we have absolutely no proof they exist).

The girls children/descendants are definetely a mystery! We know they exist since Aemon remembers them, and that they're super-important for Targaryen succession - since even Robert's claim is based on his targ-grandma - but no one seems to be looking for them! We have two characters boasting off descending from Elaena Targaryen (much older than them), so you'd think somebody would at least mention them ! Either Targ-loyalty is not well regarded, or GRRM wants to keep the mystery.

Dunk could definetely be an answer ; if there has been some extra-marital affair, they might want to keep the scandal silent (like Hoster Tully). Another option could very well be Dorne : since Maekar and Daenerys I are roughly the same age, their children could be easily be matched and since Doran has already a strong claim through her, nobody would bother remind that he's the next on the Targ-list.