I think perhaps it might be an idea if you could think of any theme you would like to play, such as an aria from an opera. There are just so many thousands of transcriptions.
Also, if you could let me know what pieces you have been playing so i can have an idea of your level.
The Liszt you mention is probably beyond most of us, but anyone with grade 7 or 8, could probably handle some transcriptions by Salon composers such as Pixis, Herz, Hunten & Sydney Smith.
I am glad your teacher has suggested this. You will have some considerable fun.
Thal