What do Unicorns want?

I am making a Celestial Warlock who has made a pact with a particularly powerful Unicorn, as suggested in XgtE. One thing I want to do is flesh out the pact and my patron, but I am struggling to find anything that would make a Unicorn different to any other Chaotic Good Celestial who happened to like forests.

I hope this isn’t too broad, shopping related or an open ended list, but:

What published official sources (Including novels) describe the motivations of Unicorns, provide examples of quests on behalf of unicorns, or provide examples of other ‘wants’?

Ideally these would be showing the unicorn wanting something other than rescuing after being trapped in a net, or otherwise reacting to something negative effecting it.

I am playing 5th Edition, but any D&D lore will be suitable.