The shadorma is a poem written as a sestet with a 3/3/5/3/7/5 syllable structure. It is supposedly an old Spanish form, though I’ve yet to see any hard evidence of its origins. Nor has anyone else, judging from the sources available. It’s more likely to be a modern response to the haiku’s popularity.
The seguidilla is a Spanish verse form that branched off from a category of folk songs that go by the same name. This poem form consists entirely of seven-line verses that typically utilize assonance instead of true rhyme, leading to a subtle but noticeable rhythm that hints at the form’s musical origins.
The pregunta (Spanish for “question”) is a poem form in which one poet recites a question and another poet recites an answer, echoing whatever meter and rhyme scheme the first poet used in their question. Solo preguntas are also possible, and easier, though it’s debatable as to which is actually better as a form.
The décima is a type of ten-line poem that predominantly finds its fame in the Spanish-speaking world. There are many variations of the form throughout Latin America and Spain, including extended 44-line variants, but the most popular would have to be the décima espinela, associated with Vicente Espinel.
The glosa is a Spanish poem form that includes and expands upon an excerpt from another writer’s work, using it in refrains throughout a poem written as a lengthy accompaniment. It seems to be structurally based on Greek odes, but there is a great deal of disagreement as to what does and does not constitute a glosa.