It's much easier to maintain existing friendships via Zoom than it is to make new ones, and I've found the same has been true in the workplace. As many people have noted, the glue of past brainstorming sessions, lunches, and hallways conversations has held together surprisingly well.
But it takes concerted effort to build the basics of a relationship when you're remote. And this effort doesn't come as naturally as inviting your new team member out to lunch. As we brought on a few new people to the team during the pandemic I noticed this chilly gap after the initial burst of welcomes and trainings.
I'm still a novice at it, but we've tried out a few basic team building tactics that have helped quite a bit.
Rotating question habit: Every week, someone chooses a question for everyone in our standup (~5 ppl) to think about for a minute and answer. At this point we've slowly built towards a reasonably deep and trusting knowledge of each other: who we admire the most, strangest food we've eaten, where we would move for one year and why. I always learn the most from the why.
Small group game: Towards the end of the day once or twice a month. Something simple with limited explanation required. This is good for exposing new team members to other teams.
Group user interviews: I've started bringing 4-5 engineers to join interviews and doing longer debriefs afterwards. Initially I started doing this to help new engineers ramp up but I had underrated how valuable it can be even for experienced engineers. If some users are internal, this can also help your new teammates get exposure to other teams.
It's well-established but still amusing to me how much this small stuff functions as the glue for more thoughtful discussions and ultimately better work.
Next I plan to set up some small cross-team lunches.