We Are All One Class, TogetherGet a large piece of paper and cut it out like a puzzle. Give each of your children a piece and let them draw themselves on the paper, and decorate it however they want. Put the puzzle back together on the bulletin board. You can put a heading like "We Fit Together", "We're One Together Class", etc.
Friendship DoorMake a large door on your bulletin board (or just cover your classroom door). Next give your children precut keys and let them decorate them however they wish. Write their names on the keys and put them on the board. You can title the board something like
"Open the door to Friendship," "My Friendship Door is Always Unlocked," "Unlock a Friend," etc.
Friendship BlizzardMake a snowman with the class. Then give each of your children a precut snowflake and let them decorate it however they want. Write the children's name and favorite thing about winter on the snowflake. You can title the board something like "Brr feels like a Blizzard," "A Blizzard of friends," "Winter Frenzy," "Blizzard of Fun," etc.
Friendship TrainHave each child trace their hand (fingers together) and then design their hand as a train. Adding wheels, windows, etc. Next have them cut their hand trains out and put them all together under a heading like "Friendship Train," "Class Train," "Our Train," etc
Blooming FlowersMake three-dimensional flowers. In the center of the flowers put a picture of each of your children. Put a caption such as "Watch as Bloom," "Friendships are Blooming," etc.