I like the feature that notifies me about ongoing invasions so I hope you could extend it towards hunts and community feasts even though they are not necessarily achievement related.

In theory they happen every 4 hours and should be unlocked account wide, but I have not spotted a community feast for two days.

Hey,

I won't add reminders that are not related to any achievement. If there are related achievements, let me know and I can add these events.

From a quick wowhead search:
https://www.wowhead.com/achievement=16544/grand-hunter
https://www.wowhead.com/achievement=16542/the-disgruntled-hunter
https://www.wowhead.com/achievement=16540/hunt-master
https://www.wowhead.com/achievement=16545/the-best-at-what-i-do
(and probably more)

https://www.wowhead.com/achievement=16444/leftovers-revenge
https://www.wowhead.com/achievement=16443/soupervisor

Some progress

The Community feasts I've never seen so would need more information as in which zone the icon should be up, the duration it's up, ...

Community feast is a bummer - as the icon only is up 15 minutes prior, 15 for the duration and 30 minutes for created soup.

There is a weak aura now Iskaar Community Feast Tracker that is able to predict the time it happens.

This was implemented in db447e5 and 0f1ef53 and released with version 49.3 and version 49.4