collaboration – Evergreen alternatives to ideation workshops

I’ve participated in (and facilitated) ideation workshops. being event-based, they sometimes take quite a bit of time to set up, especially in bigger companies and teams. While they are great for brainstorming new out of the box ideas, I find that ideas often come at the most unexpected of times. My question is, does design thinking offer a solution for ideation that’s not event-based. more of an evergreen solution or platform where members can post their ideas related to a particular problem statement over a longer time window than a single event.