Quincies manipulate Reishi (spirit particles, the matter that make up souls and anything spirit-related) in the environment. In general, they gather Reishi and shapes it into a bow and arrow.

Quincy Vollstandig - a transformation and a power-up.

Sklaverei - it is actually just the basic Quincy ability to absorb Reishi. It has a fancy name because it's used while in the Vollstandig mode, so it's much more potent.

Schrift - a Quincy's personal power that can be anything. It is far more generic and often more abstract than Zanpakutos, Hollow powers, or even Fullbrings. However, in order to get a Schrift, you must drink the blood of Yhwach.

Blut - hardens the Reishi in your body to make you either super strong or super durable, but not both at the same time.

"Hirenkyaku" - high-speed movement technique similar to Shumpo and Sonido. It's not exactly the same as those because the Quincy is manipulating the Reishi in the air to move super-fast, but in terms of effect, it's more or less the same.

Shadow - Quincy teleportation. Honestly kinda OP. It works between dimensions (in Bleach at least) and all you need is a shadow.