Digieggs
Digieggs are called "digimentals" in the Japanese version. Digieggs are small egg-shaped items that the second season's digidestined find in their adventures. These digieggs works much like the tags and crests of the previous season, allowing partner digimon to digivolve to higher levels.

Most digieggs embody the powers of the crests from the previous season. Except for TK and Kari (who keep their original crests), the three new digidestined, Davis, Yolei and Cody, inherit the previous season's digidestined crests in the form of digieggs. Each of them inherit two digieggs, and therefore the power of two of the crests. There are also digieggs that correspond to new crests.

It is also important to note that digieggs don't contribute to natural evolutions. Instead, they allow for alternate evolutions. This is important at the beginning of this season when natural evolutions are prohibited.

Digiegg Guide
Below is a guide I made to help you keep track of the digieggs and the crests they correspond to. It matches each digidestined to their digiegg, and also shows what evolution is made possibly by that digiegg.

Crest	Digidestined	Evolution	Image
Courage	Daisuke "Davis" Motomiya	Flamedramon
Friendship	Daisuke "Davis" Motomiya	Raidramon
Love	Yolei Inoue	Halsemon
Sincerity	Yolei Inoue	Shurimon
Reliability	Cody Hida	Submarimon
Knowledge	Cody Hida	Digmon
Hope	Takeru "T.K." Takaishi	Pegasusmon
Light	Kari Kamiya	Nefertimon
Kindness	Ken Ichijouji	Pucchiemon [CD drama only]
Miracles	Daisuke "Davis" Motomiya	Magnamon
Fate	Willis	Rapidmon