I dont believe in combos. Sometimes the team lose the game cause of some player says 'i dont find the X card we need!'. I'd rather sinergies. A good deck is based in sinergy: the most modelic example is Dain + dwarves. You dont need any ally specific, each ally works good, you never need X card specific to make a good job, all your hand is good for it.
More instances about good sinergies:
- low threat + secrecy
- caldara + spirit + a lot of allies
- imrahil + eomer + chump blockers + sneak + long etc
- noldor + discard pile
- dunedains + hobbits (all of them get bonus about engagements)
- etc