Obviously, we don't know which of these were perhaps 'abandoned' or parts of which were adopted for other works she felt were more worthy.
Still ... the first Symphony, the third piano sonata, the symphony for string orchestra, the sixth violin concerto, the trio (1948), and the Polish overture at least would be so much appreciated to have. :'(
Considering the mass-extermination of much of the Polish intelligentsia by the Nazi's in WW2 (Bacewicz lived in Warsaw during these years), I suppose we should be glad we have what we have - as she might have been shot.
This list came from U. of S. Cal. :
Symphony (No. 1) (1938) - orchestra
manuscript: National Library
Three Preludes for piano (1941)
manuscript: National Library
Sonata (No. 3) for piano (1942)
manuscript: National Library
premiere: 1942, Warsaw (underground concert): Grażyna Bacewicz - piano
Symphony No. 1 (1945) - orchestra
dedication: Grzegorz Fitelberg
manuscript: National Library
premiere: 28 May 1948, Cracow: Cracow Philharmonic Orchestra, W. Bierdiajew - cond.
Legend for violin and piano (1945)
manuscript: National Library
premiere: 10 October 1945, Cracow: Grażyna Bacewicz - piano, Kiejstut Bacewicz - piano
Scherzo for Violin (1945)
manuscript: National Library
premiere: 10 March 1945, Lublin: Grażyna Bacewicz - violin
Symphony for String Orchestra (1946)
manuscript: National Library
Triptych (1946?) - choir, orchestra
text(s): traditional
manuscript: National Library
Introduction and Capriccio (1947) - orchestra
manuscript: National Library
premiere: 25 February 1947, Łódź: Philharmonic Orchestra, Z. Latoszewski - cond.
award(s): Mention, Szymanowski Composers Competition, 1948
Trio (1948) - oboe, clarinet, bassoon
manuscript: missing
premiere: 4 March 1948, Cracow: S. Śnieckowski - oboe, Rudnicki - clarinet, Orłow - bassoon
Krakowiak koncertowy [Concerto Cracowienne] (1949) - piano
dedication: S. Szpinalski
manuscript: National Library
premiere: 1949, Warsaw: S. Szpinalski - piano
award(s): 3rd Prize, Chopin Composition Competition, Warsaw, 1949
Sonata No. 1 for piano (1949)
1. Moderato
2. Andante sostenuto
3. Scherzo: Molto allegro
4. Finale: Molto allegro
manuscript: National Library
Taniec Antyczny [Antique Dances] (1950) - violin, piano
manuscript: National Library (violin part only)
premiere: 1950 Warsaw: Grażyna Bacewicz - violin, Kiejstut Bacewicz - piano
Polish Overture (1954) - orchestra
dedication: K. Sikorski
manuscript: National Library
premiere: 10 December 1954, Cracow: Cracow Philharmonic Orchestra, B. Wodiczko - cond.
Suite (1955) - violin, piano
manuscript: National Library
premiere: 1955, Warsaw: Grażyna Bacewicz - violin, Kiejstut Bacewicz - piano
Concerto No. 6 for Violin and Orchestra (1957)
manuscript: National Library
A few years on and, thankfully, some of these have since been recorded and published. The Symphony for Strings on Naxos and Hyperion, and Legend and Piano Sonata 1 just a few months ago on Dux (https://www.prestomusic.com/classical/products/8711840--bacewicz-chamber-music#related).
Boy, I'd love to hear some of those still missing pieces, as Bacewicz is one of my favourite composers. Especially the 6th Violin Concerto and Polish Overture, as the mid-late 1950s were (in my view) her best years.