Many
A text can have multiple minor plots, occasionally intersecting. I've tried writing these. I don't think any of them have been published, though I still send them away. They're not going to stand out amongst other submissions.
Two
A text can have 2 plots - Plot A and a smaller, unrelated Plot B. Both have resolutions. At the end (or less interestingly as part of the plot resolutions) the reader learns how they're related. This is used in some Star Trek TNG episodes. It's an easy way to enrich an existing single-plot piece. It's also quite an easy way to generate texts - pick 2 plots at random and make them work together. I'm going to try more of these. It needs space to work - Flash and poems are too short.
One
Single-plot pieces (especially shorter pieces - Flash or poems) are often based around a big event (or an event with big consequences) and its aftermath. If the event (a sudden death, say, or discovered letter) happens early, some flashbacks or memories will be necessary to justify the reactions. The piece might become a kind of psychological whodunnit - the latter part of the text explaining, say, the suicide mentioned in the first few pages.
What interests me more at the moment is when the big event is a surprise near the end. This is a ploy that poems as well as novels can try. There's time to set things up ready to go off. The reaction section could then be short. What purpose can the earlier part of the text have?
- It can be there to add interest (lull the reader into a false sense of security) and stop the story being too purely sentimental.
- It can construct a kind of reverb chambre to magnify the event. The event lights the fuse that brings the rest of the piece to life. Some poems use this idea, the event being as slight as possible. I think the late Smiths Knoll magazine liked this style of poem.
- It can construct a scenario which the event flip-flops (a good person revealed as bad, etc). The event is ideally minor in itself
I haven't yet exploited some of the surprise-at-the-end options. I think I'll start with short forms before trying a story.