C0G and NP0 capacitor dielectrics are popular for their low or zero capacitance change with voltage. However in small SMT packages, 0805, they're only available up to ~ 0.01uF. For higher values we're forced to use X7R, Z5U or other inferior dielectrics. These might change in value by 15% to over 50% at the rated voltage.
But, whoa, Kemet has announced a new dielectric, type U2J, which can give us high capacitance values, to 0.056 uF in 0805 and 0.22uF in 1206, with C0G-like voltage properties. The largest size, 1812, offers 0.47uF at 25V. Impressive.
"negligible shift in capacitance with respect to voltage and boasts a predictable and linear change in capacitance with reference to ambient temperature with no aging effect"
I like C0G because most types exhibit essentially zero DA, dielectric absorption. Perhaps U2J will be as good.
Newark has them in stock. They have up to 0.33uF.