Blue colors was famous during BT01 New Evolution and BT02 Ultimate Power with blue Omegamon and Ulforceveedramon. And then they use blue mainly for Rookie-Rush in combination with green because of the jamming effect that low level blue digimon has. The Omegamon blue deck would be expensive because Omegamon itself is very pricy, and Ulforce deck now is no longer strong against other colors. BT04 Great Legend came with many strong power to support purple, green and yellow. Blue is a color that added only a new way to its strategy collection: hybrid digimon type.
Here is my robust blue deck using mainly hybrid digimon and the LV6 Zeedgarurumon, the main pillar of the deck. This deck strategy is removing digivolution source of opponent's digimon and control them from attacking security.
Blue Hybrid DIgimon
There is 4 types of blue Hybrid digimon, LV3 digimon [BT4-023] Strabimon, LV4 digimon [BT4-025] Lobomon and [BT4-027] Garummon, LV5 digimon [BT4-030] Beowolfmon.
For LV3 Strabimon, I only use 2 copies because I dont want to play it directly for 3 cost, I will use it in emergency only when I really want a LV4 Hybrid at end of the game. But since I have 5 copies of LV4 hybrid so it is not very hard to draw. The LV4 Lobomon, with 2 cost to digivolve, is my preferable to keep to digivolve from a Tamer, but Garummon also useful to return 1 of opponent LV3 digimon back to hand (example: return LV3 blocker in black deck). The LV5 hybrid is the best for strategy, it has jamming and cannot be attacked if there is a hybrid digimon or blue tamer in its digivolution source. So normally opponent will destroy it by reduce DP or using option card. The key point to use hybrid digimon is to end the game with one or two final surprised attacks by digivolving to LV4 from blue tamers.
Control Opponent from Attacking Security
I kind of like the blue strategy of removing opponent's digimon digivolution source. Evolution base is always giving many troublesome effects during the game such as: security+1, draw 1, memory+1, retaliation …. By removing them, it makes the opponent digimon becomes weaker and easier to cast the effect to them.
These are digimon that use to remove digivolution source:
[ST2-09] Zudomon is always the best solution to remove the digivolution source, when digivolved: can remove up to 2 cards in opponent's digimon digivolution source. [BT3-023]Angemon, a LV4 digimon with inheritable effect to remove 1 digivolution source when attacking, I have 2 copies in my deck. And the last one is new digitama from BT04, [BT4-002]Bukamon, but its inheritable effect is limited to opponent LV4 digimon, so I dont put many of these in my deck.
When you play this strategy, opponent will tend to hard-play their digimon to not give blue chance to remove digivolution source. Then this deck also have a method to deal with the digimon without digivolution source.
I really really love this combo. The [BT4-031]Marinekimeramon is the best option to return the digimon without digivolution source to hand. I feel very satisfied when I use this digimon to return their powerful LV6 digimon (so they cannot be digivolved to LV7). I can return one of my LV3 or LV4 back to hand to trigger the effect. Sometimes it's safe to return your rested jamming digimon to avoid getting destroy in next turn. The option card [ST2-14] Sorrow Blue also contributes a very important role to not let the opponent block or attack un till the end of their next turn. The other option card that takes 1 cost to play, [BT1-101] I'll Pull You Down To The Bottom of The Ocean (too long name) is a real deal. Sometimes this card confuses me on how to use it. We can use a low LV digimon to attack a rested digimon without digivolution source and just "delete it".
Need more memory for the right time
[ST2-13] Vulcan's Hammer is a must for any blue deck, with zero cost to play to get +1 memory. Tamers [BT4-086] and [ST2-12] Matt Ishida is to play to get more and more memory when opponent's digimon don't have digivolution source. If I have 2 tamers on the battle and currently has 4 memory on my side, I will digivolve these tamers to LV4 hybrid Lobomon to perform 2 more attacks to opponent's security to end the game. Opponent will normally count the digimon you have in the battle to put their blocker, but since hybrid type is introduced for Red and Blue from BT04 Great Legend, so now they have to count the number of tamer in the field as well.
LV6 digimon, Zeedgarurumon, the main pillar.
[BT4-033] Zeedgarurumon is a main LV6 digimon for this deck. I am using 4 types of LV6 digimon in the deck to deal with different situations, but I use up-to 3 copies of Zeedgarurumon. By triggering "digi-burst 2" to return 1 of opponent LV5 or lower digimon to their hand (We cannot do "digiburst" twice even this digimon has 4 digivolution source). This deck also use 2 copies of [BT4-032] Machgaogamon, by doing "digi-burst 2" to return a LV4 or lower opponent digimon to their hand. Normally I will use to return a blocker.
In this game, I play this blue deck against Yellow Chaosmon Valdur-Arm deck. It is a good game.
Correction: In this game, I did a wrong play when I did "digiburst" twice for Zeedgarurumon, for "when digivolving" digiburst effect, it can only be triggered once.