The Anderbilt brand was founded by Earl F. Anderson and used in the late 1960s on a range of floating neck electric guitars made by the Anderson-Bevers manufacturing company of Raymondville, Texas.

The unique feature of Anderbilt guitars was their vibrato mechanism: the neck was mounted on springs and could be pushed in toward the body and pulled away to raise or lower the pitch. 

Earl F. Anderson was also an Assembly of God minster, and was granted the patent on the vibrato mechanism in 1963.

Isana guitars were made in Germany from 1951 to 1974 by Josef Sandner. Sander first started a business for stringed instrument making in 1947 with Franz Himmer but they parted company in 1951. From then on Sandberg worked on his own. When Elvis was in the army he was stationed near Sandner in Bad Nauheim from 1958 to 1960. Naturally while there he wanted to buy a guitar, and he bought a black archtop Isana.

Source: Schlaggitarren.de - Isana (archived 2011)

Jeff Scott first made an electric guitar in the late 1980s as a project for high school wood shop. Scott studied music, design, business and spent many years playing in a rock n roll band. He founded Illusion guitars in the 1990s with the idea of making quality hand crafted guitars in the USA - including monster shaped ones! In 2005 Brian Moore joined Illusion Guitars to take over the finishing department. Around this period Illusion were making carved alien and dragon electric guitars. Later on Corky Shelton also joined the company . Currently Illusion offers more conventional looking designs - like telecaster and Les Paul style electrics.

Source: Illusion Guitars website (archived 2007)

Source: Illusion Guitars catalog 2005

Doina guitars were made in Bucharest, Romania. The Doina Engineering Factory in Bucharest was founded in the interwar period and was active until the 1980s. Doina made pianos, drums, accordions, wind instruments and various stringed instruments including guitars. A Doina is also a type of vocal improvised lyrical folk song unique to Romania -  coincidentally Hora the other main Romanian brand was named after a traditional folk dance.

Source: Ebay Doina guitar auction.

Penco was a Hoshino Gakki brand for Japanese made acoustic and electric guitars & amplifiers in the 1970s. In 1971 Penco instruments were distributed by Philadelphia Music Company Inc in Philadelphia, Pennsylvania. The year later Hoshino Gakki acquired the Elger Company in Pennsylvania which became Hoshino USA - the exclusive distributor of Hoshino Gakki products in the USA. The Penco brand was discontinued in the mid to late 1970s

Source: Penco catalog 1971

Source: Hoshino website

Jeroen Hilhorst is a graduate in Dutch linguistics and literature who specialized in computational linguistics and worked in the software industry. At the same time he was often making things in his father's carpentry workshop. In 1989 he combined his scientific background with his wood working skills and started designing and making classical guitars. Starting slowly he made around 2 guitars per year but now makes around 6. Hilhorst's guitars often employ innovative features to increase sound projection such as internal centre braces, double tops and reinforced graphite necks. He also offers an unusual oval classical guitar, a contrabass concert guitar, a soprano concert guitar and a concert charango.

Source: Jeroen Hilhorst website

Harshbarger Strings was established in 2016 by Jason Harshbarger (Harshbarger previously operated as Highland Strings). His interest in guitar making started in 1995 when he met local guitar builder Jamonn Zeiler and went on to apprentice with him in 1996. The next year he graduated from the Roberto-Venn School of Luthiery in the Spring of 1997 class. In 2005 he built a couple of instruments under the name Harshbarger Luthiery. He operated as Highland Strings from 2006 to 2016 before changing the company name to Harshbarger Strings.

Source: Harshbarger Strings website