The good ol’ fashioned “You all meet in a tavern, answering a poster offering gold for help…”? The action-scene, “You’re all engaged in mutual mundane task, when suddenly a band of thugs/goblins/whatever bust in looking for the plot coupon and chaos breaks out”? The “Elder Scrolls classic” - all being prisoners thrown in together? Tie it in to a character’s backstory and let them lead the other party members in?
What have you found interesting or successful, and why?
I enjoy the classics. Tavern meet, or prison escape.
But one I really like is as part of character creation everyone tells GM (secretly) about something their character would be blackmailed for. Makes for a fun campaign as these secrets are revealed.