General Synonyms:
* Small amount
* Little
* Bit
* Smattering
* Trace
* Dash
* Slight amount
* Few
* Scant
* Limited quantity
* Tiny portion
More Formal Synonyms:
* Minimum
* Sparing amount
* Slight degree
* A smattering
Informal Synonyms:
* A smidgen
* A tad
* A pinch
The best synonym to use depends on the context and the tone you want to convey.