The Lord's Prayer is a good opening prayer to say before meetings because everyone can take part. It can also be used as a model for other opening prayers, states lords-prayer-words.com.
Jesus taught the Lord's Prayer as an example for His disciples to follow. It begins by acknowledging God's presence and asks that His will would be done. Likewise, a prayer to open a meeting should begin focusing on God and asking for His guidance and direction.
Other contemporary prayers include "As We Gather Here" and "Opening Prayer for a Meeting." These and other sample prayers are available at prayerscapes.com.