Any combo that requires more than two particular cards is not reliable -- odds of its occurance are very small. I can share some if you really want, but they're not of much value.
On the other hand, combos of the form card A combines with either card B or card C, card B combines with A or D, C combines with A or D, and D combines with A or C are very useful as they increase the probabilities of combos. I'll havee to think about those. I'm sure there are good ones involving pyrohydra, and others involving bodyswap, others involving tornado -- just to list a few obvious possibilities.
And then there are combos that might use any of a number of options. In a sense catastrophe requires at least 3 other cards, but those cards can be any fire forces -- a very general type of combo.