Kouzumi

Kouzumi is a het ship between Kouji and Izumi in the Digimon Frontier series.

Canon
Kouji resques Izumi early on in Episode 3.

In Episode 16 when Izumi hugs Takuya and Kouji, Kouji is blushing, albeit, this could be out of embarrassment.

In Episode 17 Kouji gives Izumi his jacket when she is cold.

In Episode 20 Izumi is startled and grabs onto Kouji causing them both to blush.

Fanon
Kouzumi is a less popular pairing but does have some strong fans.