To my possession came a questionable item, two volumes of a Karaite siddur, circa 1550's. It's strange; there is nothing in common with lehavdil our common siddur - not the structure, nor the nussach except the nuschaos that are based on verses. It's voluminous and most of its content is, unsuprisingly, just verses and rather depressive poetry.
Actually, Karaite writers appear to be obsessed with poetry. Abe Firkovitz, yim"sh, wrote his Masa uMeriva as a one long poem, probably to bore the reader to submission.
A few things were interesting though - firstly, the most vile and vocal Karaite shows immense respect towards Rambam and often pitches Rambam versus "them" and how "they" did to him what "they" are doing to "us" . And there is a whole lot of prayer for Purim.
I thought the texts may be of interest given their obsession with preserving exact verbiage, but there is almost nothing to preserve and to compare with. It is rather strange. It also seems that they "piggy-backed" on the behind of normative Judaism, borrowing a whole lot of non-sacred routine.