I found a few invented forms which appear to be exclusive to The Study and Writing of Poetry; American Women Poets Discuss Their Craft, 1983. The book is a collection of essays from 50 American women poets, each essay provides insights into a multitude of topics from poetic genres, stanzaic forms, to writing techniques. This book provided some addition insights and background information on several stanzaic forms that I thought I had researched fully. I liked this book, it pays attention to the details.
The Octo is an invented syllabic verse form introduced by James Neille Northe.
The Octo is:
○ an octastich, a poem in 8 lines.
○ syllabic, all lines are 8 syllables each.
○ rhymed ABCxxCBA, x being unrhymed.
○ written with L1 repeated as L8, L2 repeated as L7 and L3 repeated as L6.
My thanks to Judi Van Gorder for years of work on this fine PMO resource.