What are all the ways to spell since?

"Since" is a relatively straightforward word and doesn't have any common alternate spellings. There might be some rare or archaic variations, but they're not in common usage.

However, if you're looking for ways to express the same idea as "since" using different words, there are several options depending on the context:

* For time: from, after, following, subsequent to, ever since

* For cause or reason: because, as, due to, owing to, in view of

* For contrast: although, though, even though, notwithstanding

It's important to choose the word that best fits the meaning and tone of your sentence.