If you're bored of basic cream sauce, try a jazzed up cream sauce. Lots of ways to introduce great flavors into reduced cream, including but not limited to: sun dried tomatoes, scallions, butter, stock/glace, butter, truffle butter, truffle oil, capers, lemon, olives, mushrooms, fish stock, various flavored alcohol, cheese, vegetable purees, fresh herbs. The list keeps going and going...
If you want to keep it really simple, I'd say toss in truffle butter with sauteed shrooms and serve.
If you're adding a protein to your tortellini use the fond for extra flavor in the sauce- Also, smoked meats go really well with a basic alfredo.
What it really comes down to though, is that certain pastas are often paired with certain sauces because of the pasta's ability to hold onto that sauce. Tortellini has an easy time holding onto cream sauces.