Two-handed manual alphabets

Several manual alphabets in use around the world employ two hands to represent some or all of the letters of an alphabet, usually as a part of a deaf sign language. Two-handed alphabets are less widespread than one-handed manual alphabets. They may be used to represent the Latin alphabet (for example in the manual alphabet used in Turkish Sign Language) or the Cyrillic alphabet (as is sometimes used in Yugoslav Sign Language).
BANZSL alphabet.
This alphabet is used in the BANZSL group of sign languages. It has been used in British Sign Language and Auslan since at least the 19th century, and in New Zealand Sign Language since the 1970s. Variations of this alphabet are also used in dialects of Indo-Pakistani Sign Language.
BANZSL deafblind alphabet.
This is a variation on the above alphabet, modified for tactile use by those communicating with people who are deafblind.
The sender holds the wrist of the receiver. The receiver's hand is relaxed, with the palm open and fingers slightly apart. The signer uses their dominant hand like a pen to sign on the non-dominant hand of the receiver. As a beginner, you may squeeze the wrist of the receiver between words since you will spell haltingly. Once you can spell fluently, simply put a short pause between words. AEIOU are the pads of each finger, beginning with the thumb.
Other deafblind alphabets.
From "Deafblind Manual Alphabet", on Deafblind Information, Senses Australia (links added):
Yugoslav manual alphabet.
Some signs are modeled after letters of the Serbian Cyrillic alphabet, others after Gaj's Latin alphabet, or stem from other sources. 