The so-dubbed 'violinist of Hebden Bridge', Ezra Jenkinson was born in 1872 in England. Little is known about this composer, but for certain, he was known for writing excellent study music for young musicians – mostly violinists (though his music gets transposed for viola and cello as well).
The Strad and The Violinist magazines have recommended a few of Ezra Jenkinson’s compositions for young/little players.
In 1908, The Strad published a short article discussing the difficulty of some pieces and mentioned a Serenade by Mr. Jenkinson, but it is unclear if this is a stand-alone piece or a movement within a greater work.
In 1915, The Violinist published an article titled ‘Elementary Violin Pieces, A Guide for Teachers’ written by B. Henderson (It is unclear what his first name was, but his articles were often featured).
Mr. Henderson recommends Jenkinson’s ‘La Fontaine’:
Henderson writes that the piece is a (slightly advanced) perpetual motion for both the violin part and the piano accompaniment part. Such music provides handy resources for improving intonation and finger movement.
He also recommends the ‘Bagatelle’ in G minor by Hans Sitt. He is likely referring to the 2nd movement of his ‘3 Instruktive Vortragsstücke’ for which the sheet music appears to be quite rare: https://www.worldcat.org/title/drei-instruktive-vortragsstucke-fur-violine-und-pianoforte-op-94/oclc/792925521&referer=brief_results
He recommends it as a good musical piece to practice in 12/8 time signature.
A more accessible recommendation is the ‘Petite Ecole de la Melodie’ op.123 by Charles Dancla. Each movement within contains nifty technical challenges worthy of work.