Honey & mustard is good too

Caramelised onion

Apple is a favourite in this house - just add freshly grated apple that's had a squeeze of lemon juice on it.
Pork & stilton

(wrap the sausagemeat around a thin slice, so you get a melting middle

)
Spicy cajun (just using a pre-made seasoning)

Sweet Chilli

(Use a pre-made sweet chilli sauce and put in some blanced thinly sliced spring onions)
The possibilities are endless

I make mine with the same base as sausages - 70% pork, 20% fat, 10% rusk/breadrumbs and an egg to bind it together (or 2, if it's a big batch)
HTH & good luck
Karen