Cases2[expr, f] returns a list of all objects in expr with head f. Cases2[expr,f] is equivalent to Cases2[{expr},f[___],Infinity]//Union. Cases2[expr, f, g, ...] or Cases2[expr, {f,g, ...}] is equivalent to Cases[{expr},f[___] | g[___] ...] .
The FeynCalc Book | Calc | CF |