shameless pluck:
In my friend circle im the only one throwing real parties. The most annoying thing always was the logistics of keeping track how many people come and what they might bring (cuz usually it's a, bring your favorite food/booze party).
group chats are super messy and get taken away by chit chat, so I build a simple, clean product that helps me with all that.
it's basically a virtual invitation card with extra features, like comments when people rsvp, image upload for after the party etc.
never shared it outside my circles but it's pretty polished.
hope this could be of some use for you:
https://create.party