A few other things you can use your Open Collective page for
This works like a chat function for your collective. Anyone with an Open Collective account is able to leave you a message on your page and you can respond it. You can moderate this and remove messages that are spammy or unhelpful or turn the whole feature off if you prefer not to use it. You can find out how it works here.
This feature allows you to post updates to your page and also emails them to all of your contributors. You can make these updates quite long and include image files. Some of our collectives use it as a kind of newsletter to keep their supporters up to date and to push specific fundraising drives. You can find out more about updates and how they work here and for a really good example of how a collective can use them check out Oxford Mutual aid.
Open Collective's event system works a bit like Facebook events or Eventbrite, only the money from ticket sales goes directly into your collective budget. You can find out more about how it works here but it's worth noting this is still in the experimental stages.