Thank you for your question.
Most of the time team-building activities differ from team to team and project to project. Before corona, I had (project-) team lunches/dinners, in-person firmwide all-hands meetings, or other activities with my team (like hiking, cooking, diving, or paintball). I also heard from colleagues that went skiing or climbing with their teams. Furthermore, when joining BearingPoint all new colleagues do have an onboarding training which also includes team-building activities (without giving any spoilers).
During corona, all of these activities shifted to an online format. I had wine or cocktail tastings, quiz nights, or just met online for an after-work drink. Also, the onboarding training and all team-building changed to an online format as well.
Besides the official team-building, you usually also meet up with your colleagues after work on a personal level, for instance, to have a drink or do sports together. These activities are not part of the official team-building, but help to get to know your colleagues and form a team as well.
I hope that answers your question.