I’ve been thinking about this a lot since I went back to working with my hands, covered in dust, inhaling poisonous misma for a living.
Siddhi in sanskrit refers to something like the English word ‘result’. Many define it instead as ‘perfection’, but I think this misses the point and reduces the word to a description of fantasy rather than something very real and practical. I have found no exhaustive list of siddhis, only mentions in various sutras. Normally the list of siddhis includes things like being able to shrink to an infintesimally small size, travel great distances with a thought, etc. In writing, these powers appear in the logos of the operator after many years of arduous and continual meditation and hard practicve
The deeper a person digs, the more and varying types of samadhi appear in description. Many texts see it as a starting point, rather than the end line.
I’d argue that every prolonged, meditative practice has a result. And these results are siddhis, by definition. For this idea to work, I acquaint the word meditation with Dhyana: A state where the 5 senses no longer trouble the mind and it focuses on a single point.
One need only work in a cabinet shop, or with carpenters or steel workers, etc. to find this. All of the demonstrably masterful craftpeople in any environment I’ve worked in have the ability to concentrate themselves into Dhyana while working, and have achieved Siddhi in their particular field.
"spiritual people" don’t have the authority to claim basic and more novel states and abilities. They are for all of us.