All you can read below reflects my own opinion. I just tried to put together what I saw on enemies I faced, what I read on the forums, and my own experiences.
I know you asked for combinations… but I don’t keep track of combinations I use, and combinations my enemies use XD
Emblems:
The best emblem for your banner is probably hands-down Resurrection (obtainable in Platinum and above), followed by Time Jump (obtainable only in Diamond). Likewise, these are the emblems you’ll see most of the time on enemies’ birds.
Against Witch teams, use Weakness to heavily shrink her healing. (obtainable in Gold and above)
My favourite at the moment is Vengeful (obtainable in Silver and above). As soon as I obtain Resurrection, however, I’ll switch.
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Banner set items:
My favourite banner set is Valiant. I used Angry for a long time with much satisfaction, and Blessed has its uses too, but having your birds revive within 2 turns with a 66% chance is extremely helpful in crucial situations. If you manage to have Wizard or Thunderbird alone on the board, and you give him the Chilli – devastating.
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Bird set items:
While I don’t have them all I can recommend a few.
Dragon on Red provides the highest AoE effect, it is almost a must for Red. Grand Slam, Protector’s Aura and Banner Breaker are also useable.
Twin Lightning on Chuck also provides an AoE effect and is extremely good too. However, for Chuck, I’d use either Mana or Reset, instead. Reset can delay your enemies’ revivals, and Mana provides great protection against those dreaded Venomous teams (and all other negative effects too… especially the “Focus on enemy” and “Take more damage” effects).
Mathilda goes well with the Nightmare set, or Sweet if you want additional healing.
Give Bomb Finisher, for quicker KO’ing of the banner or high-health birds, or Scissors for an AoE effect, which isn’t quite as good as Red’s or Chuck’s but still OK. Some people like Sugar Rush too for some extra healing.
Reborn on Chuck and/or Save Me! on The Blues in combination with the Resurrection banner is actually REALLY good. It can take me up to 4 KO’s of Chuck or the Blues until they actually go KO.
Artillery is an AWESOME set item for the Blues, especially useful when the banner provides an additional critical strike chance (Valiant can do that). Some people also like *BEEP*-Attack for a weak AoE effect, or Shadow Steps for a small chance to dodge attacks entirely.
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Bird classes
For Red, Paladin and Samurai are the best Arena classes. Avenger can go great together with Capt’n, too, but has only a niche use.
For Chuck, Wizard is the most common and the best option. Thunderbird is good and common too.
For Mathilda, I can especially recommend Witch for MASSIVE banner healing (careful – avoid Weakness emblem enemies!), but also Bard due to her stun chance and high damage output.
For Bomb, Capt’n and Sea Dog are both good choices.
For The Blues, pick Spies or Skulkers.
The combination Rainbird/Druid/Rogues can be decent, but careful: avoid teams with a Chuck that has the Mana set!
One of my friends also uses Stone Guard/Witch/Rogues with great success.
