Crests (Digimon)

What Are Crests?
Crests are used to let Digimon Digivolve from their champion form into their ultimate form.

After defeating Devimon, the Digidestined were sent to Continent Server by Gennai to seek the Tags and Crests. The Tags and Crests were scattered throughout DigiWorld by Devimon, after foreseeing his defeat.

The Tags are simply items that the crests are stored in, if the Tag is near its Crest, then it reacts by glowing.

Digimon Adventure (season one)
To begin with, the Digidestined were seeking Seven crests (one for each Digidestined), however when it was discovered that there was an eighth child, the children discovered that Myotismon already posessed the Eighth Crest.

Each Digidestined has thier own Crest, matching thier personality:

Crest of Courage
Bearer: Tai Kamiya and Agumon (First to digivolve into Ultimate Level)

Crest of Love
Bearer: Sora Takenouchi and Biyomon (Fourth to digivolve into Ultimate Level)

Crest of Sincerity
Bearer: Mimi Tachikawa and Palmon (Fifth to digivolve into Ultimate Level)

Crest of Hope
Bearer: T.K. Takaishi and Patamon (Last to digivolve into Ultimate Level)

Crest of Friendship
Bearer: Matt Ishida and Gabumon (Second to digivolve into Ultimate Level)

Crest of Reliability
Bearer: Joe Kido and Gomamon (Sixth to digivolve into Ultimate Level)

Crest of Knowledge
Bearer: Izzy Izumi and Tentomon (Third to digivolve into Ultimate Level)

Crest of Light
Bearer: Kari Kamiya and Gatomon (Seventh to Digivolve into Ultimate Level)

Digimon Adventure 02 (season two)
In Season Two it is revealed that the Digimon Emperor also had his own crest.

Crest of Kindness
Bearer: Ken Ichijouji and Wormmon

However, Unlike his predecessors, Ken's crest never re-acted, therefore Stingmon never actually digivolved into his Ultimate form. However, this was probably made up for, by the existence of DNA Digivolution.

Onwards
Ken is the last digidestined in the anim√© to actually own a crest.

Although Willis's digimon Terriermon digivolves via normal digivolution, there is no evidence to suggest that Willis has a crest.

Although it is revealed Terriermon can digivolve through Golden Digi Eggs. This allows Terriermon to digivolve into a Golden version of Series Three's Rapidmon.